Are these 1.8L L-Jet ECU's interchangeable? Options

[Jason74914]

1974 1.8L with stock L-Jet Bosch FI

I need to replace or repair my ECU which has the following on the label:
Bosch part # 0-280-000-103
Porsche # 022-906-012-G

I've located a 1974 1.8L donor car (inoperable and history unknown):
It's ECU has a label with:
Bosch part # 0-280-000-111

So, the difference in the Bosch # is last three digits: "103" vs "111"

Also, the donor ECU does not have the Porsche # on the label, but I tried to cross-reference, and I'm coming up with: 022-906-012-B

So, difference in Porsche # is only the last letter: "G" vs. "B"

Interweb shows the "B" associated with a 1975-76 VW Bus or 914.
(I have no idea why the donor car--which is definitely a 1974--has the "111/B" ECU in it.)

Question: Can I replace my "103/G" ECU with the "111/B" ECU?

Thanks,
Jason