we have a tv that has been on the wall and now we need a stand. Is it possible to order a stand now if I provide the model # etc.?

Honestly if it's over a year old on the wall you might try the manufacturer or other sites Amazon eBay etc

I do not think Best Buy would be able to but I haven't tried. I put the model number on ebay and got a power board for my TV though. I bet you can find it on ebay. A lot of electronics repair shops sell parts there.

More then likely.