Certainly you can setup a separate bass remote.
You could get anything from an open box item, just having scratches on the heatsink, to missing screws, or perhaps needing repaired as well. The point is, there is a reason it ended up in the yard sale, if it ends up where you have to put more money into the item as it needs repair (worst case scenario), you will be closer to having just bought it new.
I remember the yard sale on CACO, some items were better or worse than others. Many were reasonably okay and usable, so most people got usable stuff, others needed re-coned. Just know it’s a gamble and you have to be prepared to take the risk, that’s why it’s a yard sale item.
I personally never felt the yard sale prices were worth the risk of getting junk. Wasn’t exactly dirt cheap, and if I’m spending that kind of money, might as well get something new with warranty, or look locally for second hand items that are cheaper and work.