Evening all. I've just acquired a Gamo Centre in rough condition that I want to get sorted (ish) and it's in need of a new seal. Been scouring the net and all I can find is a one peice unit here (pw020)

https://www.gunspares.co.uk/products...Centre-Pistol/

And not the two pieces that are in there at the moment ( rubber seal and a nylon washer)

Am I right in assuming this has superceded the original parts does anyone know please?
TIA