sash balancer - I think it says 11600-17

Most Andersen balances have some variation of the "11600" number, but there's another number that identifies the balance.

I scoured your photo (using some kind of enhancing software beyond my own comprehension) for a marking, and I think I may have found one. See the flange, where the staple is fastened? That flange looks like it has some kind of code on it. Can you read it, or photograph it very closely? It probably is the part number.