There's the 5 year rubber replacement, but there's alot more o-rings and seals that are not part of it that I would change as well.
The o-rings sealing the oil pump for example. They would be nice and hard for sure.
There's also the rear crank seal and water pump seal.
For the carbs, I'd send them to Floods for full strip/inspection and replace everything rubber.
Rocker cover seals.....
Inlet manifold o-rings to head....
Radiator cap....
Gearbox strip and inspection......replace front seal.
Oil can lid o-ring......
There's probably more.....
CPS have a good graphical breakdown of part assemblies to look at....
https://www.cps-parts.com/menus/rtx/parts_4.html