Pool Replacement Part Help

I am needing to replace many top plates and unsure of which part is correct. A plate measured 6 1/4" in length with about 2 1/2" between the screws. The pool is 18’ x 48" and at least 10-15 years old. I would appreciate any guidance/recommendations.

We’d be glad to assist you. Do you have any pictures of the plate without the top rails attached? Could you also provide a picture of the top cap?