UPS made my day! Question?

[GunnutAF]

I just got my lastest order in from Glens Armory, 1000 rnds of Lot #10 XM193! This was the bulk box and as normal I go through it to get the dinged cases out to shoot first! Good news seems like the monkey's a UPS were kind and didn't through it around much as I hadn't found any dings! Now to the question I have , seems about 40% of this box has mixed headstamps? I have a mix of the normal LC 10 then I have that 40% that has the NATO Lot #10 head stamp. Neither of my other two lot's of #10 have this, it just hit me a strange -first time I've seen this!