FWIW, I did rebuild a replacement AQ130C a few years ago. Engine parts like rings, bearings, and seals are still available, but you need to be creative with your searches. There really isn't much reason for VP to continue to stock legacy engine parts, so for those parts, you switch to Volvo car engines. Be aware that there are a few components that are marine specific.
During your inspection, be sure to check the head for cracks, especial around the valves. I went through several until I found one worth keeping.
As far as checking out the boat itself, keep in mind the age of the boat and all the systems. Like it or not, everything is an unknown until you check it out. I ended up rebuilding my whole boat from stringers, transom and deck, to fuel tank and all related components. None of it is rocket science but it does take time and money. I have no regrets whatsoever from rebuilding my boat. Just make sure you have your eyes open when you start.