If you made a good deal? It's usually the buyer who wonders if he got a good deal.
This will come across as rude, I wouldn't have sold it. It's a garbage PSU. Based on ancient tech with no good features. I would have kept it as a backup/test unit, or given it to a friend. For example, I had an old Antec Smart power 450W PSU probably 10+yrs ago. I upgraded to a better unit and threw that one in the closet. A roommate had hers die and I gave her that one. I care about my name/rep and wouldn't sell anyone such a unit. As USAFRet be happy you got anything for it. You did fine.