Welcome to the forum.
The Zodiac Pro 500 is the same boat as the earlier Pro 9-man (4.7m), effectively renamed. It's a shallow to mid V hull which is fine for sheltered waters, but does have a tendency to slap in the rough stuff.
The boat material is PVC (Strongan Duotex), and are fairly easy to repair with 2-pack glue and the right ambient temperature. You mention patches, so take a closer look to see there aren't any bulges and it's completely air tight. Zodiac also introduced Hypalon on their leisure boats, but pretty sure this will be on much newer models.
The 500 was available with integrated hull fuel tank, or tanks fitted in the console or under the bench seat. Check hull for finish, especially the keel. Surface abrasions are fine, but anything that exposes the fibreglass weave or chips needs to be dealt with.
Also check the console for spider-cracks in the gel-coat. On my Pro I had these marks, they weren't structural but shouldn't be there.
The tubes are held on at the bow (webbing strap) and at the transom. Once partly deflated the tubes can slide off the hull rail. Might be worth deflating to check condition. Also useful to clean sand that gets lodged in this area and acts as an abrasive between the hull and the tubes. Zodiac have extensive dealer network, but be warned, prices aren't cheap for their parts.
Engine. The Yamaha 75hp 2-stroke is a great mid sized outboard. Plenty grunt to weight ratio, easy to work on with extensive parts available. Check for service history and that it starts and trims, without hesitation. Will need annual impeller change and gear oil change as minimum. Only trouble is the Pro 500 is rated for a maximum 70hp engine. Sure you can run it with 75hp, but insurance will be an issue given hull rating.
The Pro 500s I've seen have 60hp 4-strokes or lower. Seems to be preferred choice.