Thanks for posting! Your channel balance assembly resembles either the S351-22 with a 1" shoe or the S390-22 with a 1-1/8" shoe. To determine which series is needed for your window, look over the dimensions from the diagram below to confirm the depth of your bottom shoe.
I'm sorry to say that I would not be able to determine if the stamp from your balances is incorrect for your window. The stamp on the balance is how we determine the weight range the balances should be able to carry to support the weight of your sash. However, we are unable to cross-reference your stamp, unfortunately.
That said, you'll need to obtain the exact weight of your sash to determine the exact stamp option you need.
There is a chart that lists the weight ranges each stamp option can hold.
