Help with M1A1 .30 cal ammo box please

[MarkM]

Picked this ammo box up at a yard sale because of the latch on the end and because the color confused me. I've since learned that it is a .30 cal M1A1 ammo box (from late WW2 to the Korean War?) and that the latch on the end was for attaching the box to a Browning machine gun. I've seen some descriptions that say "early production" - how can you tell? The dark brown color appears to me to be some kind of a primer as if someone was refurbishing it? I've seen discussions on "red oxide" finishes but I don't think that is the case here? The lot number is somewhat hard to read but I think it is "SL B93857". Any information would be appreciated as I'm wanting to sell this box. Thank you in advance!  Mark

 

[robinb]

It attaches to the side of the M1917A1 tripod. Someone has over sprayed red oxide primer over the original OD.

[MarkM]

Thank you!