ACG,
                                    
                                    Thanks to everyone who took the time to send updates; I have
                                    included all that I received. So here (just in time for weekend 
                                    fleamarket hunting) is the May 8 version of the Argus 21 table. 
                                    
                                    Mike Reitsma
                                    
                                    Need
                                    Film 
                                    to             Shutter
                                    Serial  Serial  Film  Cock    M/F    Speed 
                                    Number  Located Guard Shutter Switch Dial      Reported by       Notes
                                    ----------------------------------------------------------------------
                                    2870   bottom   yes  yes    top              Bob Kelly
                                    3320   bottom   yes  yes    top              Bob Kelly
                                    3814   bottom   yes  yes    top              Bob Kelly
                                    5880   bottom   yes  yes    top              Bob Kelly     
                                    7434   bottom   yes  yes    top    solid     Mike Reitsma
                                    16491   bottom   yes  yes    top              Bob Bowman
                                    16517   bottom   yes  yes    top              Carl Turner 
                                    17960   bottom   yes  yes    top              Carl Turner        [7]
                                    19218                                         Modern Photo       [4]
                                    19919   bottom   yes  yes    top              Willis Bird
                                    20793   bottom    no   no    top              Fred Schwartz 
                                    24763   bottom    no   no    top              Bob Kelly
                                    26078   bottom    no   no    top              Bob Kelly
                                    30442   bottom    no   no    top              Ken L omax 
                                    40006   inside    no   no    top              Fred Schwartz 
                                    42149   inside    no   no    top              Phil Sterritt
                                    42852   inside    no   no    top              Bob Kelly          [1]
                                    46117   inside    no   no    top              Charles Spickard   [6]
                                    47757             no                          Stephen Lyons
                                    50705   inside    no   no    top    plate     Bob Kelly          [2]
                                    61804   bottom    no        back              Richard Kimmel     [8]
                                    63612   bottom    no   no   back    plate     Bob Kelly          [3]
                                    64785                                         Modern Photo       [5]
                                    
                                    
                                    [1] PC connection on back to right of viewfinder.
                                    
                                    [2] Revised speed select dial.
                                    
                                    [3] 63614 has no clip, does not need film to cock shutter. SN is on
                                        BOTTOM, but the type font is larger than the others and it is
                                        etched in the opposit direction as the others, M/F switch is 
                                        on BACK to right of viewfinder, also has revised speed select
                                        dial.
                                    
                                    [4] First Argus 21 serial number as reported in the 1955 Modern Photo
                                        used camera guide, quoted in Phil Sterritt's serial number list. 
                                    
                                    [5] Last Argus 21 serial number as reported in the 1955 Modern Photo
                                        used camera guide, quoted in Phil Sterritt's serial number list. 
                                    
                                    [6] Has old style shutter dial.
                                    
                                    [7] 17960 has a much crisper grain leatherette as compared to 16517.
                                    
                                    [8] Shutter speed dial & screw are smaller. To be able to read serial 
                                        number the camera must be held with base plate facing up and with 
                                        with lens facing away from you. On my other model 21, this is just 
                                        the opposite. [Email from Richard]