In my game I have your two adapters "<x> to 3-point" with the same picture in the shop and the same name in the shop. They're different when I buy them; one being the telehandler to 3-point and the other being the frontloader to 3-point.

Neither of them can be sold back to the shop at the selling point in my game.

I would suggest that you give your two adapters different pictures and names in the shop. It would be good if they could be sold at the shop selling point too.