Acceptable to ask seller for option to return a component?

I’m a bit new at this hobby, so am wondering if the option to return a purchase within a short period of time is accepted practice or just naive?

I just opted out of a potential sale of a 15+ year old component @ $3,000+ because the seller would only sell ‘as is’ with no option to send back if I felt the item did not appear as described. 

Is it acceptable practice for Audiogon sales to ask the seller for this option, or maybe ask only if the seller is a dealer?