Heatstamping?

I agree. Actually, I think it's impossible to stamp it there cuz the smallest size/font for heatstamping is about the same size as the width of the strap, and also not to mention the 2 grooves on the strap. The leather must be a thick piece and completely smooth.
If you REALLY want to get it heatstamped you might wanna try getting it done on the zipper flap where it says the country of fabrication

Where are the two grooves?