Even if the initial 'get in' cost is $000.00 as this one was? I rescued it as it was about to be tossed into the dumpster.
Maybe, maybe not. What you need to do is this:
First, track down all of the parts you'll need (barrel, bolt, stock, sights, trigger group, etc.) and add up the total cost for everything including shipping. (Keep in mind that finding all of these parts won't necessarily be easy.)
Next, find out what what a good gunsmith will charge to install the barrel, headspace the bolt and whatever else you need him to do. Add up those two figures and you have the total cost of your rebuild project.
Compare your total rebuild cost to the $400 that a complete 1903 costs from the CMP.
You may find that you'll be hard pressed to beat the CMP price by doing it yourself.
Good luck though and let us know how it turns out.