Mike, very nicely marked. Just a suggestion (what I did with my DP Long Branch) is to write out what DP means on a piece of paper, roll it up, and put it in the buttstock hole so that a future generation without your wisdom doesn't try to shoot it.
I recently bought a 1918 Lithgow(not a DP). The stock is marked "R" above "MA" (I believe R means "repair" and MA is the Lithgow arsenal mark -- please correct me experts), with a date of 2/46, indicating a new butt; the forend and handguards are all marked with '45 stamps (indicating replacement of the original wood). Apparently during the Arsenal Repair, along with the wood, the Armourer replaced the button cocker with the late model version (stamped OA'43), and the nose piece with the late model version without the stacking swivel hole (no serial # stamps). 5thMD is stamped on the top of the receiver (not sure what this means) and another set of receiver stamps is been overstamped with XXXXXXX.
Robert