Alrighty! I've dug up a likely suspect for our man, Hiram Gilbert.
North of Syracuse, NY, a bit East of Fulton, there's a region known as Six-Mile Creek. In 1819 Hiram Gilbert and his brother Andrus built a grist mill there. In 1821, Andrus built the first store in the town. It became known as Gilberts Mills. At some point between 1821 and 1863, there were two stores, two blacksmith shops, two shoe stores, a grist mill, a sawmill and a post office. Gilberts Mills was on the down slope of prosperity by 1868 thanks in large part to the Midland Railroad which had no stops there.
An older book I found, talking about the region, lists the chain of ownership of Gilberts Mills, which should help narrow down when these razors were made.
http://books.google.com/books?id=jOs...9%2C191&edge=0
That suggests that these razors date from 1833 to 1844, the time period when Hiram Gilbert owned the operation.
The newer history I found of the region treats the whole era as a shrouded mystery, so it would probably be news to local historians that there are Hiram Gilbert branded razors.
I'd be willing to bet money that these razors are from
that Hiram Gilbert, though. Most likely made in Sheffield but it's not out of the question that they're simply very well-made lookalikes.