The Orion is an all round great boat
. I want one too. The only thing I know for certain to look for is blistering in PSC during part of the 80's, but this should not be a major problem and in line with most boats this old. I don't remember which years.
Outside of this, regular things I would look for, such as:
Warping and shape of hull
etc etc and etc.
The usual stuff you find in books
Take careful notes. Things are fixable but you can judge the costs if you keep track and guess it up later and adjust your offer.
Recommend getting a complete survey
Keep us informed and good luck!!