Ask for a photo showing the eyepieces. The GAT had small, concave eyelenses (it used, like all its predecessors, Erfle eyepieces) and hard plastic eyecups, whereas the BGAT had the standard largish, flat eyelenses of many other Zeiss binoculars, for instance the Dialyt 10x40 BGATP or the Dialyt 7x42 BGATP, and rubber eyecups.
The BGAT was, in fact, the last model of the 15x60, so in that sense the seller is right. (15x60 -> 15x60 GAT -> 15x60 BGAT)
Hermann
Hello, Hermann.
I know that at the first 15x60 was made, then 15x60 GAT and then 15x60 BGAT. THe BGAT itself was made for some years, I suppose that the last serie of BGAT's was made in 1998 or even in 2003 but not in 1993. So the BGAT that I was offered was from the first series of BGAT as BGAT's were made from 1992.