The stamp is the branding of an eagle globe and anchor on the heel. Only USMC authorized boots have it and if it doesnt then it isnt an authorized uniform item.

I knew alot of people who used to wear the non-authorized "high-speed" boots in the desert because...
1. Lighter- every ounce counts
2. Comfortable- Hurts walking everywhere
3. Less expensive - compared to $200 pair of danners

Now unless its authorized issued uniform item you cant wear them on your feet.