TOUGH CALL........... Actually I got stung the same way...........
A few years back I bought an extra head from a guy on ebay....... The head sat for a couple of years. Until I was ready to use it.
..........and guess what. It had a crack in it! The head had been completely rebuilt and new seats/guides everything by them.........$500 down the drain... but it looks BEAUTIFULL sitting on the shelf.....
Actually I have an extra set of new valves because of that!!! forgot about that....
...........but 2 years later I was not gonna hold it over this guys head.
I ended up spending over 1K on my present head. DON't ask... hehehehe....
I would say this head is no different than most used heads you are gonna run across. This head was rebuilt before and the car it came off had ~190K. If I were you I would slap in new stem seals and be done with it. The guides have average wear. Nothing that is screaming at me to replace them. The exhaust seats are ok. I would of re-installed this head if I had to.....
If this is a stock turbo its going on it will be fine. If you are planning on running some serious boost........ uhmmm well I would be doing new seats.
Tough call chuck. I don't know what to tell you.