Model 80 'Type 2' (386DX-20MHz), 27C512 EPROM x2:

U157: FRU 15F6597 (identified internally with same FRU)
U158: FRU 15F6000 (identified internally with same FRU)
BIOS Revision '0', date of 07 OCT 1987

The pair below identify internally in the same relative order and have the same date

U157: FRU 15F6637
U158: FRU 15F6639