Washington - Franklin Series 1908 - 1921 Paper And Security Marks

Dear all,

I have in recent came across a Washington 1 cent stamp(probably coil stamp sold by vending machine). There was something unusual on the paper, as I found a stripe of marking on the stamp that resemble a grill, but I don't think this version carry 'grill'. So that left me with an option of paper used to print the stamp, could it be the ordered paper from vendor, and that is the security mark to prevent counterfeit?

Enclosed the picture for your review. And appreciate any advise given, thanks.

Cheers,
Nelson

The vertical ribbed lines are caused by the dispensing mechanisms in vending machines in places like railroad depots or post office lobbies, which naturally used coil stamps. The lines would be considered damage by most collectors, but evidence of the dispensing/vending technology of that era by some. The curved cut is also a result of passing through a vending machine which cut off the purchased strip of stamps.