I have a VSP Labs Gold Trans Mos 150

I bought it new back in the 1980's and it is in near mint condition (about as nice as a piece of equipment can be after 30 years). It's in the original box and I think I have the manual, etc. It work perfectly when I retired it some years ago. I haven't tested it out... I don't have a separate pre-amp... but just wondering what people think. I want to sell it. Should I spend a few bucks at the shop I purchased it from to have it tested, etc., or would I likely not get much for it? 

I did find one that sold for $600 last year and it wasn't as nice as mine, but I also saw one that didn't sell for $325. 
I think you need to at least make sure it works...whether the cost of a professional check up will be returned in sales value is maybe - there might be someone looking for one, and Audiogon members are not hesitant to make a low offer if they feel you are asking too much...it was a great amp in it's day