I've seen parkerized milspecs with blued and stainless barrels. The stainless barrels seem to be fitted better -- they're also of the one-piece design.
Similarly, I've seen stainless loadeds with either blued barrels or stainess ones as well.
I wish the factory would be more consistent with what they put into the gun. I've seen milspecs with fantastic barrel fits (with almost no play on the hood area), and loaded models with poorer barrel fits also.
Each gun is just so individual and quality of fit can vary greatly from one gun to the next.