I agree on condition. Chances are good if someone kept it covered/garage kept, gelcoat looks shiny, seats are in good shape, carpet is in good shape, and so on that everything else was equally cared for. You're not gonna spend time/$ keeping everything else up and then skip oil changes and routine maintenance.
My grandfather used to say look at a renter's utility bills. If they're paying those then they're going to pay their rent. Same principal in effect.
Case in point...
I bought a '79 Sea Ray cruiser once where there was some wood rot on the helm, teak was worn, and stored outside uncovered. I was young and didn't know any better took it home and progressively found the engine block was cracked, stringers were rotted out, transom was bad, etc. All said and done I paid more than I bought it for to fix everything.
I later bought a 2005 Regal cruiser. Looked brand new, had all the original manuals, everything worked, had a cover, and low hours. Had the boat about 7 years now and no trouble. I've always stored it covered, done the routine maintenance, etc.
My rule of thumb is always assume what you can see is only a fraction of what you can't. A boat with signs of wood rot is likely completely rotted out. If the engine won't run for whatever reason assume it will need to go into a shop for a tune-up or rebuild.