1903 original sling from 1940 1903a3 worth

[7,62x51mm]

I have an excellent condition 1907 sling marked BT & B Co, no inspector initials and without any date. It is a Belber Trunk & Bag Co, Philadelphia Pa manufactured sling late WW1 and post war. Took awhile to find out the data, it came on a WW2 M1 rifle

[Beltfed]

I have several bass frog slings. I never paid much attention to them. How do you tell if it’s a Boyt sling?