Alternator wiring issues

[Austin's 86 LX]

My alternator went out Monday morning and I traded it in at a local j/y when I got my new one. Stupid me didn't think to check and make sure they were the same
My "old" alternator had been put in by the previous owners back in '09 and judging by this picture the wiring harness and alternator put in were meant for an FI car o_O
So I went back and grabbed the plug from the 3-pin carb alternator at the yard and I'm planning on soldering it on in place of the 4-pin one (I don't have enough faith in myself to replace the wiring harness) and I was wondering if the wire for the ECU can just be snipped and left alone since I don't have an ECU.
The sooner I can get this fixed, the better. I've had to spend my spring break without a car

tl;dr can I use a carb alternator in a carb'd car with an FI alternator wiring harness, replacing the plug and ignoring the ECU wire?

[Dr_Snooz]

Bump.

[Austin's 86 LX]

I got it taken care of. I was thinking of the red and white ECU wire as going TO the alternator when really it is coming FROM the alternator. I spliced on the 3pin connector and it's working fine