Mystery letters on Quantegy boxes

[Dr ZEE]

I am not sure why I care, but still
I've noticed these stamps on 5" quantegy boxes. What the heck are these? (see pic)
Sharing of clear knowledge or pure wild guess - both are welcome and encouraged
See those red letters: "MG", "DH"

 

[My Name]

Thats the initials of the dood who glues down the corners of the box. It's like the lables on Lush products. The next step will be a cartoon like drawing of the blokes face...

 

[Golden]

so, that bastard's responsible if the tape is fucked?