I was at a police shooting event where S&W was a major sponsor. They had a S&W M4, a real M4, with 1/7 marked 14.5 inch barrel, 3 round burst, etc. on display. I believe it was made up to show whomever (.GOV?) that in time of crisis, they could step in and make a military grade M4. After a few people began asking about it, it got put away.