Nope, neither of them do anything - left or right - and that's in LEDs, LCDs or IR3s. Ask John Rice - the Angel designer - and then retire 10 paces until the fuse burns through!
I'm only kidding, but they really are a cosmetic, nothing more.
They came about because somebody saw one of the early Angel prototypes with a short cylinder under the barrel instead of the usual right-hand end cap. The cylinder was actually part of an externally adjustable LPR that didn't go into production. Observers didn't know this and just came up with their own assumptions as to what the gadget was and the volumizer was born.