How lucky we are then that VW had the foresight to chamfer the shaft bores in anticipation of one of their future OEMs not sticking to spec. Those thoughtful Germans...
It's just a shame that they chose to not chamfer both sides, then we wouldn't even need to have this conversation. Maybe they figured that they could give parts sales a boost by not doing so.
So, for Mr. Wild Man, and any others reading this thread for T4 engine build tid-bits: If you are tempted to flip your rocker shafts around to give the rocker arms a nice new unworn surface ro ride on: you may get away with it, But, you need to carefully measure to make sure that you can.
Should be easy enough to do. Try fitting each shaft onto the pair of studs where you are intending to put that particular shaft, non-chamfered side towards the head, without using the rocker stands. The shafts will probably be held up by the tapered shoulder(s) of the studs. Measure the gap between the shaft and the rocker mounting pad on the head and compare that to the thickness of the rocker stand at that point. If the gap is less than the amount that the rocker stand holds the shaft away from the head (plus a bit for good luck), yer good. Otherwise, resign yourself to using the worn surface of the rocker shaft. or decide whether you want to experiment with adding enough chamfer to the non-chamfered side of the shaft to give you sufficient clearance.