"Fred" posted these pictures of his restored Rod-Bayonet 1903 Springfield and web gear on the Culver's Pages.  He was kind enough to give me an OK to post some of his pictures here.
  The pictures show how the early Rod-Bayonet Springfield rear-sight bears a relation to the Krag model 1902 sight.  When the Rod Bayonet model was abandoned with 1905 changes to the Springfield, surplus useable parts became available to repair model 1902 Krag sights with discarded '03 parts.  (Fred cautions his present sight base is a reconstruction, but, the leaf, slide, and knobs are correct 1903).  Fred's Springfield is still chambered for .30-03.
  Thanks Fred!

In 1960, in USN Boot Camp, I was issued SN 4003 as a drill rifle.  It had been converted to 1906 standard.

Thanks again Fred for the pictures and information on the Rod Bayonet  Springfields.

The abandonment of the Rod Bayonet Model 1903 and the 'Updating' to 1905 changes had to leave an abundance of discarded, as well as, unused RB '03 sight parts in storage at Springfield and Rock Island.

The Krag seems to have remained in widespread use with the U.S. Army, Navy, National Guard, and Military Schools well into the 19-teens.  It certainly saw reserve and training use during WW1.  When handled roughly, the Slide-Lock Screw of the model 1902 rear-sight was particularly vulnerable to being bent or sheared-off.

The availability of RB '03 sight parts that interchanged with model 1902 sight parts had to be a real boon to repair and refurbishing of Krags at U.S. Arsenals.

The yardage graduations on model 1898, 1902, and RB '03 rear-sight leafs have the same spacing.  Differences in Cartridge Trajectories were compensated for in the height and curvature of the different model sight bases.

The peculiar RB '03 Slide-Lock Screw is commonly seen on many Krags with the model 1902 sight.  It would be interesting to know if this always indicates repair or if it is a result of 'model changeover', with Krags still being manufactured while the Rod Bayonet Model 1903 was starting production.  (Produce new type knobs that will  work with both out-going and new Service Arms).   

Oh heck, I'm happy to share with you all any photo's you'd like to see!    I'm always looking for excuses to use the phone camera that my wife bought me. It's a good one I think.

That is a very nice looking Rifle. I have seen one just like it at the gun shows here in my area and the gun with it is also the  author of Description of U.S. Military Rifle Sights. The model of the Springfield you have is not out of place as it does have a modified Krag rear site on it till, it was change out with a totally different site.