These two photos were shared in the SOG vet facebook group and it is pretty interesting. One, because its not a picture out floating around. Two because of their carbines. The carbines are mostly CAR-15 uppers on M16 lowers, or XM177s with fized M16 buttstocks swapped in place of the telescoping stock. I don’t know and there is no way to know unless a SOG armorer who did it or knew about it decides to get on the interweb and start talking about it. Which is highly unlikely.
There are other examples of this and I have read of at least once account of an M16A1 being chopped up to have a shorter barrel and not an actual XM177. Like many things with SOG, it will probably remain a mystery unless some SOG vet speaks up about how these came about and why.
I can only guess since the Indigenous team members preferred the shorter adjustable collapsing stock. Maybe the team One-Zero liked the storage in the buttstock for extra medical supplies, or the indig team members were superstitious and had to have a jade Buddha in the butt stock. It honestly could be something as simple as that.