Contary to popular belief the M1917 saw quite a bit of service with the U S Army and USMC during WW2, both as drill and range rifles in training and as a weapon for non combat service troops, who often ended up in the thick of it regardless (such as at Bastogne, there are photos of cooks at Bastogne carrying the M1917), and as combat rifles for Marine mop up squads on the smaller islands when the standard Garands and Springfields were in short supply due to the massive troop build up in expectation of an invasion of Japan.
The M1917 was also commonly issued to U S Airforce airbase sentries. From what I've read (maybe true maybe not) due to concerns that curious British civilians (especially kids) in some areas might be shot by mistake they did not let the sentries carry loaded weapons and sometimes removed the bolts from these rifles, so the sentries were mainly for show. Due to pressure to get as many new recruits as possible into action Airmen seldom received much if any training with small arms, so safety was a concern.
State National Guard outfits had been asked to turn in all Springfield rifles in their possesion to be refurbished and issued to combat troops, with the promise of as new M1917 rifles and ammunition as replacements. One source from a western state wrote that they received the rifles, in excellent to new condition, but only received one five round stripper clip per rifle. They never got the chance to do any shooting with these rifles, so these remained as new when sold of as surplus. Photos of these Guardsmen on a mountain patrol show them carrying various sporting rifles and a few Krags, rifles they had ammunition for.
Another National Guardsman wrote that on arriving at Fort Dix all the excellent well cared for Springfields his outfit brought with them were confiscated never to be seen again and they were issued M1917 rifles. When word got around some other Guards units left their good Springfields at home and bought some unserviceable beat up drill rifles to turn in when they got there.
Probably the best buy on an M1917 would be those sold to Canada, I think these went mainly to the RCAF.
A veteran Canadian armorer wrote that for some unknown reason the bolts were shipped seperately, and not serial numbered to the rifle. This armorer and his mates spent weeks carefully handfitting bolts to these rifles and checking headspace, then numbered each bolt to the rifle it had been fitted to.
So if you find one of these with matching numbered bolt its likely a hair better mechanically than its contemporaries in equal condition.
I have seen an old newspaper article about the sale of these rifles to canada, the number of 80,000 rifles was mentioned, there may have been more.
Many Canadian M1917 rifles were given to Denmark to replace rifles lost in the war. The rifle was so popular that the Danes continued to issue these to arctic patrols for many years, until replaced by a clone of the Winchester Model 70 also in .30-06, and these occasionally show up in far flung ranger stations even today.