Acceptable to ask seller for option to return a component?

You certainly have the right, and probably wise to get a return commitment, in writing.

Also, even if listing says 'working' ... write seller via the service, i.e. eBay, Reverb  ...ask questions, and get clarifications in writing which you can then refer to if a dispute arises.

Note: eBay, PayPal, Reverb have buyer protection. PayPal: get an invoice from seller for the item(s) via eBay so you can pay for 'goods and services' (not send money to friends or family which is not protected) avoid using zelle if you can. 

The extra fees for protection have gone up; reported sales/taxes are more of an issue, you might need to offer to pay the extra fees involved with the system like PayPal.

Fund paypal with your best credit card so you have the CC's 'fraud' protection. Sometimes I call the CC company prior to a purchase to confirm coverage and ask what might be needed for a successful claim.

CC Fraud often has a 14 day delay, so get 30 day return privilege's if you can.

If you buy a warranty, check if it is transferrable, might help with a re-sale

there is an important difference between a return because not working properly/not as described, and you just didn't like it...difficult for both buyers and sellers...

Sure why not?

Worse they can do is say no. 

even if you return something on Crutchfield on Amazon, it's not without a lot of costs and consequences, so I am usually very careful with the return option.

Most seasoned buyers on audio forums have a different approach: research the hell out of what I am buying before buying AND/OR if I don't like it, will I be able to resell it at a loss I am willing to accept. 

I learned this early at my own expense and paid dearly. I bought new/open box speakers for $1500 that checked off all the wrong boxes: sounded terrible, had no value on the used market, a sneeze would scratch the veneer, etc. 

certainly agree there is no harm in asking...