serpentine belt for 1988 4.3

It did happen to someone else... ME! It's been a few years though.

Yes, you can buy the belt for the same engine without A/C and use it. It should work just fine.

One thing to watch for - there is an idler pully/tensioner just below the A/C unit that the belt runs around. The head of that pully is plastic and tends to get brittle over time. It is very easy to break so don't be surprised if you snap it putting the new belt on. Luckily, the replacement is also cheap! (under $10)

If you haven't done it before - that tensioner is the only thing you have to move around to get the new belt on. Unlike many older cars, you don't adjust by moving the alternator around.