@flyfisher its important to ask questions when buying anything used. I’ve bought an inaccurate used airgun when I didn’t know better. I even watched a video of the seller taking a game animal with the rifle. In the video I’d noticed that he was holding pretty far to the left. I figure it was pretty windy that night. I didn’t ask about it. That’s on me. Turns out that the damn rifle shoots curve balls regularly. I bought another rifle from him that leaked IIRC. I swiftly sent it back to him. He was cool about it and refunded my money.
My suggestion is this, be open and honest when asked about accuracy and issues. You may also wish to get ahead of the problem and advertise this, but if you do, be prepared to lose a few dollars. Some guys can re-crown, re-barrel, or polish the barrel on an rifle and yield improved results, but will submit lower offers because they know that if you could correct the issue that you would and you’d probably keep the gun. In their minds they’re potentially buying a problematic air rifle.