A 1920 Lithgow butt will have the Lithgow shield and the month year date (8/20) stamped on it when it went into store if not it is a replacement or is heavily sanded. The OSTERR GENDARMERIE is post WW2.
AFPATRIOT
Your rifle is a run of the mill one some have lots of stamps if they have had a hard life others no. The 3MD is Victoria. The numbers other than the serial on the action and barrel which also match are inventory numbers for the MDs. There maybe several if the rifle was returned for a rebuild or went to another MD. The butt will have date stamps showing the return to store.