That is interesting Mr. Mike, that Winchester holds that expectation of dealers. Candidly over the course of 35 years as a LEO, you are the first person to ever make that statement. I am not doubting it in the least, just surprised I have never heard it before now. I am wondering if it is a new company philosophy for some reason - any idea?
I am not aware of any federal law that would prohibit civilians from using ammo marked as LE only, as Mr. Steve noted. Since I spent many years ordering ammo for various agencies I worked for as the head instructor for that office, I have also noticed a "trend" in my view anyway, on LE marked ammo. Normally on the ammo lists I ordered off of, LE only marked rounds were packaged in boxes of either 50 (normal) or 25 (rarer) for handgun ammo. So I have basically felt it was more of an in-house designation for the manufacturers to refer to 50 round boxes more than anything else. At least based on the government ammo lists I have looked at for years.
I will add one comment on one specific +P+ round that we encountered in the past. My agency issued the Speer Gold Dot 9mm loads in standard and +P (both 124gr), and +P+ (115gr) so folks could carry the round they felt best armed with. We quickly discovered the +P+ loads were damaging the rollers in our issued MP-5s. Once we discovered that, as the MP-5 is in my view a very hardy weapon, the decision was made to no longer issue the +P+ loading for duty use of any kind.
I am a big fan of Speer Gold Dot ammo personally. But based on this situation, I have simply elected not to use any +P+ loading, as I simply feel most major brands of ammo in various calibers in either standard or +P loads will do fine for me. Again, this is just my view, but I wanted to offer it for what it is worth.