Cool video, thanks for posting ! As chance would have it, i traded into a nearly NIB Sport II earlier today (and I immediately started shopping for a deal on some new handguards, which is why this video caught my eye.)
This rifle (presumably) would not be my main SHTF/Zombie Invasion go-to gun, and I don't do recreational 60-rd mag-dumps, so now after seeing that it's the ends of the grips that are prone to heat damage, something heat shields won't do anything for, I'm thinking I'm probably fine with the stock grips (but i love the look and feel of the Magpul handguard, so if I can score a deal, I'm still probably gonna get them
.)