A couple of thoughts on the matter... first is that with the boat being a 1989, this is going to be before Grady White switched over to the SeaV2 hull, so your boat will be a SeaV1 instead. Some people care about this, whereas others do not. The SeaV2 hull is what they currently use on the new Grady White models and for a 22' boat it switched over in 1992. The SeaV2 hull is going to provide a more comfortable, smooth and drier ride as opposed to the SeaV1 hull. On top of that, in 1997 I believe it was when GW switched over from using standard marine grade plywood to using a product called Greenwood XL. The latter is supposed to be a bit better at resisting rot as opposed to your standard marine grade plywood, which can be beneficial on an older boat that is now 34 years old. If you do get water intrusion, which is quite common on a boat that is again now 34 years old, it can make for a very costly fix, sometimes being $10k+. And one last thing that I'll mention is that linked below is the brochure for 1989, which it talks about weights of boats as well as their specs.
A 1989 GW 227 Seafarer, of which the particular boat you're considering is called a 227 with the I/O motor, is going to have a dry weight of 3,705 lbs. Also per the brochure, and I'm not sure if the 351w you mentioned is rated at the same horsepower level, but that's with a 180 hp motor. Comparatively, the same year 226 Seafarer weighs 2,875 lbs and a 228 Seafarer weighs in at 3,000 lbs even. Of which my point would be that you're going to have an extra 700-825 lbs more weight with having the I/O motor and if it's only 180 hp, then I think it's going to be very sluggish to get up on a plane. Comparatively, and yes this is by no means an apples to apples comparison, my boat has a dry weight of 3,510 lbs or almost 200 lbs less than the one you're looking at, yet it has 225 hp and the "sweet spot" imo for my boat is in the 225-250 hp range. With your boat being heavier than mine yet having potentially 45 hp less, I again think that could be an issue. On top of that, the other 1989 models mentioned above had a maximum horsepower rating of 280 hp, which again makes me think the boat would struggle a bit if it were a stock motor with only 180 hp to it. I think knowing a bit more about the boat, the asking price, your budget, the actual condition of the boat and so forth would give us more to work off of, but depending on the price, condition of the boat and horsepower levels... it sounds like it might be something to pass on. Good luck!