So if that is right, around Juky or Week 28 was when the updated drive was being used. These models had a new insert/eject mechanism. Later Sony models OA-D34V-02 or OA-D34V-22.'There were two basic types of disk drives: So my guess it that it would work? But maybe those boards have been upgraded with more RAM. I cant recall but I do know people have put Plus ROMs in a 128k, effectively making a 128ke model. As for having it it ROM, maybe that does work. Its not that the 128k does not support the HD20 per say, its that there is not enough RAM to load the drive from floppy. Keep in mind you have a memory ceiling of 128k still. There is a model difference in the drive so its easy to ID. But I actually have NO clue what the issue will be. So if the drive is the updated version, those ROMs may not like it. I forget when that happened, maybe around week 20 or so? I would have to look that up. Then came -B for the updated eject mechanism in the 400k drive. Then -A which I think is the same as the priors. The first batch of ROMs had no -A on them, that was done a few weeks into production. The ceramic 68000s are rather common around that time, in fact they seem more prevalent on the 512ks.
FYI, that board is not early and on par with the week 44 based on individual chip dates.
