Beautiful condition... especially the bluing.  I'm no expert, but I would hazard a guess that this was NOT modified by the Springfield Armory.  I'm sure that some of the more senior members could speak to that better than I!  Do you know what your barrel length is?  It's most likely a cutdown, and the front sight is definitely not original.  What do you suppose the screw on the barrel just forward of the receiver is for?

Paul