I've found an armor glitch with the Riot Armour's Head wear in Lonesome Road. You can equip the 1st Recons beret with the Riot armor helmet it just merges with it and gives you extra power ups!
I'm fairly sure that the 1st Recon Beret has been notorious for it's glitches. Such as, being meshable with the Avanci thing from OWB. Sorry to burst your bubble.
A glitch I DID find though, (I don't know if anyone else experienced this) there was an invisible Tunneler in the collapsed overpass tunnel. It wasn't like a Nightkin where it would shimmer in the light, it was invisible as if it weren't there. It kept attacking me and I couldn't see where it was until the little aim thing turned red. I fired and killed it and its invisible body parts became visible and floated in mid air. :3