Well, I was able to return the one that didn't fit and find a used part that does fit.
However, the correct fitting one still has a vacuum leak (a little bit smaller than the original). The idle is a bit better now, but still having issues. Idle will surge & pulsate. Sometimes it will even stall.
So I think the best course of action would be to get a new one, but I just want to confirm this is likely the source of problem before dropping $140+ on it. Thoughts?