I have not seen the boat since it was owned by the previous owner. However, here is my take on the situation: If I was looking for a nice, low-hour, Version 'A', liveaboard GH37 on the cheap, I'd start by figuring out what the blisters would cost to fix. I am not sure about the condition of the hull paint - but maybe it needs a paint job too. Factor that in. Then, figure in that I might have to replace the 8kw genset (prob just needs some work though - it's a Yanmar engine on the front end, after all). However, I can't believe those low hour Yanmar mains will require anything more than service and cleanup. But I'll figure in the price of new peripherals - alternators, starters, hoses, belts, water pumps, etc.
Now add it all up. Take that total dollar figure and double it. Subtract that amount from the asking price and that's what I would offer. The boat has been on the market for a while. They very well might take it - but this is important: only if offered AS IS, WHERE IS. Don't forget, they've been to survey and gotten shot down before. Not much risk for me, as I know, structurally, the boat is built like a brick you-know-what. Worst case scenario, those little pea-shooter Yanmars are pretty cheap - and I already doubled my estimated costs. It will still be the absolute cheapest you will see a Great Harbour for a long time. We just didn't build that many of them!
Just the opinion of a guy who is pretty familiar with Great Harbours.