maybe someone else knows more to it but i cant see why you cant bolt them in, they will fit, its the rest of the setup that has to be modified - ie rebuilding the head and clearances, shims and whatever as well as changing some settings on the dizzy and carbs to suit the cams. thats my educated guess.
the 2tg stock series of cams had some sets with pretty aggressive grinds and as time progressed emissions control and head design saw they got toned down a lot. so there are a lot of stock cams with aggressive grinds on them that can be put into your later model 2tg engine.
you can also get a regrind for about 100 per cam in brisbane im told, which can be whatever specs you want.
on a turbo street engine, ie 3tgteu you wont be able to run a very agressive cam grind