Newscotlander,
It seems your statement,

"Apparently, no one ever found a hand stamped Inland in the serial number range 6219689-6449868. I have yet to see a photo. "

...still rings true. I was hoping that you or phrogpilot would have posted a photo of his carbine on that CMPicon thread when he returned. I see now that he never got back to you. Anyways,...it's always fun learning more about these carbines.