There is no DP stamp there is a D ^ D stamp on the receiver which is the Dad and Dave Government stamp mark. the P on the knox is a replacement barrel P.
The part stylized R is a rust stamp. The number on the bayonet boss is from an earlier rifle. The number you showed on the bolt is the PA number which will also if it matches be on the action under neath the closed bolt handle. You don't show the rifle serial number on the rear of the bolt handle. The butt plate is not original and there may not be any stamps on the butt.
Hey c'mon big fella! I thought you were in my side re the P on the barrel