That's not a serial number but a part number. Here's a list of part numbers in order of manufacture: The ones with question marks may not have seen production 820-0001-00 revision 0 820-0001-01 revision 1 820-0001-02 820-0001-03 820-0001-04 my Apple II which has a 1979 production date 820-0001-05 820-0001-06 820-0001-07 memory jumper blocks eliminated 820-0001-08 ? 820-0001-09 ? 820-0044-01 RFI revision started production 1981 820-0044-A ? 820-0044-B ? 820-0044-C 820-0044-D Apple Collector wrote: > Can the following motherboard serial number identify a computer as > distinctly either a II+ or a II? > It is 820-0044-D. > > I know I've seen an Apple II plus with a serial number 820-0044-01. Is that > a coincidence? Or am I reading something that is not a serial number? > > In either case, does the above sequence identify a mother board as > definitely NOT an original Apple II? > > Thanks for any insights. >