It probably could, although most cars I ever saw with the seat belt interlock have had that system disconnected back when the cars were new.Thank you! So I just did a quick search. It appears this could interfere with the starter working, if it malfunctioned?
This may help:
Thinking about this more, I think there was a TSB on having dealers bypassing these in 1975 or 76, but don't quote me.
IIRC, the usual disconnect was the seat weight sensor under the seat. Again, don't quote me on that. It's a very old memory from the 70's.Very entertaining, and an annoying no-start waiting to happen. What a ridiculous waste of time and resources, including multiple boxes and a huge "analyzer" devoted just to this.
I unplugged the interlock button and the car still starts. I have also tried starting the car without belt buckled. Still starts. So it appears it has been disabled as you said.
I'd like to find out what exact modification was made to bypass this thing back in the day, to confirm it was done properly and won't be a failure point some day. That said, whatever was done has lasted 48 years so far . I will attempt to locate "the brain".