All About Pocket Knives

Picked up a decent LB7 Schrade today at the pawnshop for $15. Cleaning it up a little, I see a number - R2119 - stamped lightly on the edge of the front bolster. Very neatly done - looks factory to me. Does anyone know what this signifies?

OK, I found a discussion of serial numbers about 3 pages back in this forum. Looks like over a million of these knives were made and a lot of them were serial numbered. See "LB7s by other companies?" Thanks