Part numbers of all cylinder head components are the same for R and GT.
Triumph playing their silly little game don't make any parts or service info available to non-TFC owners. Must be top-secret-squirrel stuff. Can't have the peasants knowing what's going on, can we? So we don't know about valve check intervals/lubrication/etc. that you mention ... Only someone with a TFC handbook could tell us if there are differences there.
But I'd nearly bet it's alla da same right through the range.
So I dunno where they get their claimed extra 14 RWHP from. Looking at that dyno chart in Post 6 with its hugely different "Delta" (transmission losses) between the TFC and the others - for which there can be no reason? - one might wonder if the extra 14 to start with is fairy floss? Final output is only 5 RWHP extra and that could occur between different bikes/dynos/operators/mileage. Torque figures and rev limits are the same. As Doc says, the differences are most likely all cosmetic.
Still waiting on Doc to tell us if the exhaust outlets are a different size from 32mm. Or anybody else with a TFC.... Mittzy?
But really, who cares? They go pretty good...............