[time-nuts] FA 2 Counter variations

[Perry Sandeen]

Learned List,
Checking the Ebay listings for the FA-2 counter I saw three variations. One had just BG7TBL on the bottom of the face plate.
A second -since deleted- had BG7TBL XX- XX- XXXX (date).
A third one was labeled  BG7TBL 20190622. All had wildly different prices.
So is this just some form of date coding or is there some technical difference?
Regards,
Perrier