Anderson 2573558

It's hard to tell what you have without seeing the original. After doing some digging, I've seen that number correspond to our 82-037 mortise lock, which in turn uses the 82-043 thumb latch and either the 82-316 left or the 82-317 right key lock (the handing on Andersen doors is established from the outside looking in and which hand you use to pull the door open).

That said, these are just educated guesses. You will need to carefully go over our pictures and information to confirm that this hardware matches up.