alright none of your pictures actually posted. you can't copy and paste for your personal collection, you need to upload them to a photo sharing site like photobucket.com or such and copy the direct link URL in order to embed the image into a post.
I also have a low serial number springfield, dated to 1912 manufacture with a 1918 barrel and remington replacement bolt(that's what the R underneath the bolt handle denotes). so since your gun was given a remington bolt and a replacement barrel made near the end of WWII it is perfectly acceptable to assume that your rifle used extensively during WWII at the least and more than likely saw some service towards the end of WWI as well before it was rearsenalled and packed away for a rainy day.
the politically correct answer is that low serial number springfields are unsafe to fire and CMP does not allow low numbered springfields to compete in their rifle matches. however I am of the train of thought that believes that many of the unsafe to fire rifles were weeded out over the course of the last 80+ years and since yours was fired enough to require a new bolt and barrel that it was definitely given the proper stress testing to ensure that the receiver is stable and safe to fire. it is a heated debate among springfield collectors and nobody is changing their positions on the matter any time soon but what I would recommend is test firing in a controlled environment from cover to make sure it is truly safe, if you don't want to take the chance then sell it, there are plenty of collectors like myself that shoot their low number springfelds that would love to add another one to their collection.
all guns lost in a tragic smelting accident.
I never said half the crap people said I did-Albert Einstein
You can't believe everything you read on the internet-Benjamin Franklin
Bean counters told me I couldn't fire a man for being in a wheelchair, did it anyway. Ramps are expensive.-Cave Johnson.