We also have no idea what he had on under that coat. We analyzed that one for years... lol I mean remember those days?? Was it a gun, an animal, a shovel, a stick, good grief it went on and on and on. We know he has at least a gun and a knife or possibly a box cutter so what else is under that coat? Seems very logical that BG had a blue coat based on the photo of him. This scene was bloody so I'd say it's very likely he got bloody and took off the blue coat.
What we also know is nobody else on the trail after 2:13 saw the man or described a man matching BG.
Another interesting note I just saw in the PCA is it says near the end of Libby's video the man is seen and heard saying down the hill. I am curious if they have some other images of part of BG.