If you're looking at the 91K, you need to probably talk to JLD. The only way I've seen those offered is with the shortened wide handguards. Those should have shields.
If you're looking at the fullsize 91, my experience with my PTR is the wide handguard (with shields) fits without any problems (except opening up the front pin hole a bit), but the regular skinny handguard and the heavy barrel of the PTR aren't friendly with each other.
I'm using a wide handguard on mine, and tried to modify a German surplus skinny handguard (hey, it was cheap) to fit. All I got out of that was scratched finish on the barrel--the heatshield itself was too narrow to fit over the barrel and I was too stupid to notice as I was working on it!
I got my wide handguard from POF. JLD has some of unknown manufacture (guessing POF...) too. Top Notch theoretically carries some US made ones as well, but you know the story with them.