The armour is invisible - looks good on some and a bit silly on other chars <img src="/ubbthreads/images/graemlins/biggrin.gif" alt="" /> - stats are there.
As I didn't wear the armour but had it in my inventory, I saved after the fight, spoke to Swen and then looked at its stats. But you're correct, talking isn't necessary, the armour upgrades as soon as you've killed the last bug. Cause I had it in my inventory (so my mouse hadn't run over it), I could save and had a better start in reloading for stats than having to fight the bugs over and over again if I had worn it.
Kiya