Types of Vest Pocket Kodak.
Original VPK, made between 1912-1914.
All original VPK cameras had a shiny black enamel paint finish except for plated parts and the brass escutcheon lens plate.
Although having the same internal parts as all VPK's, the earliest cameras had a noticeably flatter viewfinder retaining ring viewed from the front.
This circular port carried the red window for checking the exposure numbers on the backing paper as the film was wound-on after each exposure. It was otherwise without markings.
Except for the circular access port, the camera back was smooth and without markings.
When fully extended these had square edges making a 'box' shape. Cameras made after 1914 all had pleated bellows.
At extra cost the camera could have a multi-element f8 Kodak Anastigmat lens instead of the usual meniscus one.