I think paying an hour or two of shop time would be money well spent. a great deal can turn in to a huge pain in the neck if you miss something... say water in the outdrive, leaking bellows, rotten stringers or transom, etc, etc... l
I had a similar sized boat with a 4.3 / alpha drive in it and it was great for all around. would run into the 50's easy, plenty of power to pull people and didn't do too bad on gas (we're talking boat standards here...). Lots of people and shops around that know how to work on them, parts are reasonable and easy to come by, etc... I think a lot of people would agree that for in inboard / outdrive of the type it sounds like you're interested it's a good combination. Also a small enough boat that won't be too difficult to get in and out of the water.
If he bought it from a dealer he's taking a huge hit selling it at $3000. I would be very cautious about the inspection; especially the engine and any repairs to the hull. I would go through it with a fine-toothed comb. It sounds like he knows something you don't.
Around here that boat from a dealer would go for twice that amount and about $5K from a private seller.
Ask the guy if you can get it inspected by a marine mechanic and have it gone through top to bottom.
boats are selling cheaper and cheaper here... and we're literally surrounded by water. There aren't near as many out on the sound or river this year as last, not even on some of the really busy lakes that we go to is the traffic as heavy. economic downturn and fuel prices are driving prices down a lot... what you would think something was worth from a year ago just doesn't apply any more - at least not in my world...
It sounds too good to be true? I'd expect it to be almost twice that price, especially if it's that clean? But it is an 89' boat, 19yrs old. It is a great size, & combo, highly manueverable, in, & out of the water, and one of the best engines for dependability, power, & economy, if it suits your purpose. It maybe needing manifolds, & risers, by now, if they haven't been changed recently, especially if used in salt water (not cheap, but worth the money if so) I'd consider them normal maintenance on a boat, as long as they're not bad enough now to cause engine problems? If you find it's all good, I'd jump on it in a flash!