Part of me thinks: Not worth taking the risk, just get the right ones and swap them if in any doubt..... now in theory, if you are not removing the head and swapping the bolts, you are not breaking the contact from the head gasket, so would you need to changethe gasket?
Other part of me thinks:
whats the worst that can happen?
Water in the oil? Loss of compression? The you'll have to do a head gasket and renew bolts, which is the only thing to do to fix the issue in the first place! VW tolerances are massive son unless you are running 200bhp plus. Id leave it and if it aint broke dont fix it!!
The only reason I doubt the need for it to be absolutely correct is that many many years ago Paul B and I did a piston change in the middle of the night 400 miles from home and a limited tool kit....and had no choice but to re use the head gasket and the head bolts etc. I needed to get home. And it got me home, and then took several hard turbo'd thousand miles later and 7 years on, (despite not having moved much) its still good and producing good power....! And when/if I get the car on the road again I'll continue to hammer it till it breaks! Or I upgrade the head bottom end or something!