Acceptable to ask seller for option to return a component?

Absolutely yes.  I ask all the time and rarely get a no as an answer.  Heck, I even asked if I could return a dog once as I wasn’t sure she would play well with the other dogs and a cat we had at the time.

All the best.

+1 @chayro TMR tip top to trade with. No caveat emptor w/ them.

So @djb2573 if you’re hesitant don’t buy. PM me please for a special on a bridge in Brooklyn. NOT!

On Agon you see if they are a Verified Dealer and see their recent and lifetime feed back ratings. There are many 100% folks. This ain’t ebay.

If possible get to know your seller. I have had several pleasant back and forth messages when making a purchase on Agon. Some now a cyber pen pals. One guy came to my house! Great fun. Here there are many "birds of a feather."

OP clearly states in cases of "item did not appear as described" ...

If you have the chance to speak to Him. By talking to Him you can easily sense if he is good person to deal with.If he is not nice then don’t do the transaction.Definitely you have right to ask  the seller for return options. If they already stated no return option? Stay away.

You can always ask and they can say no.  My take for buying audio gears on Audiogon is always "no return" except:

• Item is not as described
• Seller / Dealer specifically stated return would be acceptable (usually with restocking fee)