Only if he sells the FWB600 and uses the money towards a P70, they are totally different animals. I'm not saying its not possible to convert a SSP to a PCP as it has been done before, but a lot of time and machining would be required.
AirArms RN10/EV2 Stock-2007 Big nikko FT Kit
AirArms NJR100 Hawke Airmax SR6 HFT/SFT Kit
Feinwerkbau 600 10 metre
HW77K-zeiler 6-24x44 Work in progress
Webley Vulcan .22 Lovely old relic