For sure. People get really, really weird when they buy and/or sell stuff (which, of course is shirt, if it's somebody else's stuff.)The purpose of a pre-buy is to gain information, so do whatever you think is beneficial to you to get the most information about the aircraft.
Here’s something to consider about prebuys: there is not any guidance or industry standard on prebuys, unless the two parties agree to complete it and record it as an annual inspection. I’ve done prebuys that were more like preflights because they’ve already bought it and I’m flying it home, but I’ve also done prebuys where the buyer didn’t want an in depth inspection for one reason or another. “Don’t look too hard, it’s a good [price, paint, avionics, nostaliga] yada yada yada and I really don’t want to pass on it.”