I have found two different SBEC2 PCB board 4517652 and 4632377
I am guessing that the 377 was the early release and my examples utilize the 87C257 latch chip
The 652 was able to use the 87C257, 27C256, SST and Toshiba chip.
I will be checking part number on the chip with the parts fiche.
Any additional information will help.