Thats what i thought but i realized they are serial numbers.1983 boards 01286780, 01432016, 01262216, 01286765, the 1986 boards, 019859380 and no label on 6th. Your question did make me look closely. All 6 are the same except for the RAM. The RAM chips on the gold ones are Hitachi 4481832 or Motorola 4481897, and the non-gold ones are Hitachi 4481987 or OKI 4481832. I found a sticker on one newer board "To replace card order p/n 69X5507" that I had not seen before so now but a web search turns up nothing.