Lot of guessing going on here. Sport45 has the start of it right.
First generation Winclean had large primer pockets with large flash holes to vent the "hotter" Dinol into the case without cratering or backing out the primer.
I don't know the initial policy but the last I looked, they said it was OK to reload.
Then they went to small primers because Dinol is first, "hotter" and it does not take as much to light a pistol powder charge, and second, because it is more expensive than styphnate. Headstamp is NT for Non Toxic.
They said not to reload, but most folks ignore them. I know shooters who look for small primer .45s so they can use the same primers in .45 and .38 etc and not have to change out the primer feed on progressive loaders.
I have seen small primer .45s without NT headstamp.
Are they using regular small primers or just quit marking for NT but still lead free? I don't know.