Do we know if they had regular open sights when delivered? I am pretty sure Winchester was numbering all these bolts so that number was not typically done by the USMC IIRC.
Yeah WRA did number the bolts new from the factory. On the sight issue, it's always been assumed they came with sporter barrels and some, but not all were rebarreled with target barrels for the Marine shooting teams post WWII. The documents we have from that 373 order in 1942, do not make specific mention of the barrels though.
But when you dig into it, the Marine Model 70's are a tough nut to crack. There really isn't a lot of documentation on this topic, and it relies heavily on first hand info. Which some of that seems to contradict each other. I know my friends who regularly dig in the archives, have only found a few more documents than what has already been published and nothing that is solid proof to either prove or discount what has been stated in a book.
I have read a bit about the pre war rifles and have owned a few for a long time. I recently picked up two more from a new acquaintance. My first research question was does the serial range 40,000-50,000 include all calibers manufactured by Winchester. I now believe it does. We know that 20+ M-70 calibers were made during the 1936-1963 era in ten plus models. Does anyone know how many pre war M-70 calibers were made for the M-70 platform within the 40-50 thousand range? Does anyone know how many 30-06 rifles were made within that pre war, 40-50 thousand range or how many models(featherweight, nm, carbine etc.) there were in the 40-50 thousand range?
It is also known that other branches and agencies acquired pre war M-70 30-06 rifles during this era and thatt other branches and agencies acquired m-70 30-06 rifles in the post war era.
I've been trying to unravel this for a while and it's tough. We haven't found much in the archives on the Model 70's honestly. Not like the other Marine sniper rifles, where they detail so much.
I can only find three calibers that the Marines actually ordered, .300 H&H, 30:06, and .300 Magnum. The .300 H&H, I can only document a few, the same with the .300 magnum. Like on those I think I have Marine counts with quantities of 10 or 12 or less. They seemed to be used in the 1000 yard matches of any rifle, any sight. Like the Wimbledon Cup.
On the 373 the Marines ordered in 1942, Winchester says in one document that all of those were 30:06. But it doesn't specifically state the barrel ordered, but the "books" have always said it was just the sporter barrel.
When Captain Van Orden and Marine Gunner Lloyd did their sniper tests right before WWII, they concluded the Model 70 Target model G7044C was the best sniper rifle and had recommended the Marines acquire a 1000 of them. But the Marines decided instead to use the (1047) 1903 NM and Special Target rifles they had onhand, from the Marine rifle teams and Divisional Matches. But this is the description of the ideal Model 70 sniper rifle, straight from the Van Orden Report.
And here is the WRA order in 1942. I have several docs on that order, but this one is probably about the best info wise. I think this is also quoted in Senich's book too, so this isn't like groundbreaking, but it has great info on it. This is where I'm getting they were all 30:06.
On your other questions I don't know. I've read too that the other branches acquired Model 70's, but I have no proof. I've tried to find documents on the Marine model 70's and they for sure are the hardest one to find any actual real info at the National Archives. And honeslty some of the documents contradict themselves, and it makes you wonder really happened. But without actually finding the documents, it's just all a guessing game. It's really been the one that has left me scratching my head the longest. But these might help you some mjmd.