Thanks for your reply.
The 'older' GPS is serial #10803, purchased in July 2009 from Sparkfun
The 'newer' GPS is serial #17745, purchased in July 2011 from Teledynamics
I have obtained the firmware numbers for both GPSs, which can be seen in this image...http://users.tpg.com.au/users/daveg/stuff/EM-406a_Firmware.png
I do not have a datasheet for the Motorola M665C, but the software that uses it's serial NMEA and 1PPS has a high reputation giving the correct time, as observed and reviewed by many observers in the astronomical community, where precision timestamping is paramount.
I have made a video of the time display of the various devices. This image
shows the display over 3 seconds. I have labelled everything and I hope it is clear and understandable.
-the device with the older EM406a was left for 24 hours to ensure the Goldcap was flat.
-all devices were started and fixes were obtained all devices were reporting 6 satellites or better
-the device with the newer EM-406a and the device with the Motorola GPS are giving the correct time
-however the device with the older EM-406a is running 1 second fast
-after about 12 minutes, the older device correct's the time by counting the 40th second twice. This is detected by the device and it raises an error "Almanac updated.... "
-thereafter all 3 devices give the correct time.
I can also make available a brief 12 second video if need be.