Thanks Wombat, it seems your 1917 was rebarreled out of service, otherwise the number would have been xxxxed out and the new one applied. I have one the same.
Prior to 1925 the barrel was the control item, it's number was normally transcribed onto the new part, after that timeframe, the receiver became the main part and barrels were numbered to match.
Can you tell me if there are three stars in front of the nocks? and is there a number (1,2 or 3?) or a letter (s or L)