Louras, I don't claim to be a licensing expert (just a JF owner/pilot) but my reading of the relevant Tecnam service bulletin (
http://reservedarea.tecnam.com/Utili...e-952ceebccda1) is that all the changes for the MTOW increase are largely procedural and applicable to all serial numbers. You get the ASI rescaled (no doubt to reflect the whole knot or two change in critical speeds), install a new placard or two, and update the flight manual. If my memory is correct, there was an intermediate bulletin some years ago taking the MTOW from 580 to 600 kg but that's obviously been overtaken by the new bulletin.
I think the LSA versions of the P2002 were always 600 kg MTOW and they remain limited to that in jurisdictions where the LSA rules apply. Someone may correct me on the history of the LSA line if I'm in error.
I've not bothered with the MTOW increase for a variety of reasons, one of which is that the regulatory and licensing environment in Australia for private aviation is now so oppressive that I see myself eventually re-registering the aircraft in a recreational aviation category. That transfer will be easier if the log books etc show a weight at or below 600 kg.