Who made this T2 band?

[Bubba-7]

I would not speculate on a manufacturer. From my small sample of original five million block Inlands, I have 5.2, three 5.3 and a 5.4 with the double slash. So off hand, I would say a double slash on a 4.9 seems early.
Any type 2 band on a early 4.92 seems a little early.
However, if I had a contract to make a new band type, and the prime contractor was screaming for them, After I made the first few hundred/thousand, I would send them to be sure there was not an unforeseen problem with them, before I made 50,000 or 100,000 of them. I would want to know early on.
I would check the barrel for the parkerizing trace of a type 2 band, wider than a type 1 band. If it is there, It is original.
And guys, I have seen three types of slash marks. There is the double slash, the single slash and the half slash. The half slash is common on IBM carbines and to many, an unknown variant. And some times the single slash can be rotated. Maybe not another variant but made on Mondays.