Sir William/Woodsheal,
Thanks for the great info!

I think I'm following everything now...and I think I found the source of my confusion. I guess I was equating the "new invented knapsack" to the envelope style knapsack.

Am I correct in my understanding that the "new invented knapsack" is the type that has one large pocket that loads from the top and then on the flap side, the pocket is a closed pocket with a vertical center slit which ties closed?

How was the envelope style knapsack that was in use during the F&I period constructed? I'm assuming that the appropriate materials would by any type of heavy linen or hemp canvas...or were the military issued ones made of leather or "hair-on" cowhide? If linen/canvas, were the flaps painted as was done in the American Revolution by the continental troops or not?

I don't think I've threadjacked here, but I apologize to the OP if I have. I think my questions and the answers given will help the OP answer his questions too.