I wouldnt let the differences in rifle slings, fore ends, magazines, rails, etc, lead you to believe that this guy is fake. So many commercial companies are throwing their gear at the US military for "trial" purposes, or there may be tons of back orders on official stuff that in turn allows variances on different items to be used. PLUS... I know for a fact that soldiers over their are having their families send them things to help with their duties that the military does not issue or does not issue enough of (lip ice w/ sunblock, tan colored tape and/or spray paint, silly string, wet wipes, etc). Gloves are one item that the military allows much leeway on. When you're crawling around on rocks all day protecting your hands is important, neoprene or other such rubber gloves do the trick nicely.
The mag in the first photo is a "PMag" made here in the US by a company called Magpul. They've developed an entire line of items to "enhance" the M16 and M4 series of weapons. The soldier that is the topic of this video is using a standard USGI STANAG (STAdard NAto Gear) magazine. Both are fine magazines and work well, the British just placed an order of 100,000 of the PMags for their SA80's. The slings are of a newer design and a huge improvement over the standard strap that went from buttstock to front sight. Both of the designs allow the rifle to hang freely at the front of their person and the need to sling it over the should is eliminated. The optical sight is a 4x Trigicon TA31, they are an optic of the highest quality and each sight alone is worth $700 or so on the commercial market (I own that exact model).
I can not comment on the grenade launcher, but nothing seems too out of place on that. My biggest question is why did he not lob a few of them in? It has a max range of 400 yards, yes?