Question about S14 ECU's

[s14nut]

I'm still a newbie with cars in general, so I wanted to ask you guys about the S14 ECU's. Anyway, I brought my 95 S14 into a shop because it was starting. The technician there told me that my ECU (or ECM) is the cause of it. So, I bought another ECU from someone else. It came from a 95 5 speed car but the sticker on the ECU was different from mine. The sticker on my ECU says 3C. I forgot what the sticker on the other ECU is (I think it's H something, I'll double check on that).

Anyway, since the new ECU came from a 95 and it was 5 speed, I thought it would work on my car. The technician then calls me the next day saying that I would need to get an exact ECU 'cause the car still doesn't start.

So, my question is was the technician correct and I need to get the same exact one? Or any 95 5 speed ECU should work in my car?

Thanks for any help and sorry for the long post.