Fell off the wagon with a K-31 and Argentine Mauser

[Calfed]

I am no expert so not being contrary. Just trying to educate myself. I thought the engineer and calvery were basicly the same with different sling arrangements? Calvery being side mounted and the engineer being in the standard location and one having a bayonet lug and the other not?

That is not my understanding.

Per Ball's "Mauser Military rifles of the World" the "Mountain Carbine" (also known as the "Engineer's model") is in a standard carbine configuration stock and the "Cavalry carbine" has the full length "Mannlicher" style stock.