Ah! Those were sometimes sold with a blade etch that said "ADAMANTINE EDGE"
Wade & Butcher sold them as "The Celebrated Old Army Razor 1776". They seem to have been a fad between 1845ish and 1855ish. A search on 'Celebrated Old Army Razor' will turn up a lot of them.
Here's my pair of the W&B version:
http://theshiveringbeggar.com/wp-con...8/IMG_7698.jpg
Henry Lummus' first Antique's article has a picture of one of the Fenney models.
It's possible to assign a rough date to them because there's an 1851 advertisement for the Wade & Butcher model and the Fenney versions come in both Fred Fenney and C.T. Bingham versions, showing they were made near the end of Fenney's life and just after Bingham took over.