I just came across this thread, while researching siderography. I have a couple of these transfer rolls myself, though without a transfer press they are really just glorified paperweights. This one was used on a railroad bond. It weighs about 6.5 lbs. American Bank Note Co. sold off thousands of these when it divested its archives.
One more question. Was the stamp material hand fed or was it somewhat automated?
A very late answer: you are confusing a transfer press with a printing press. Transferring an image from a metal roll to a metal plate was a completely separate process. Once the printing plate was created, it could be used on a printing press. In the early days of stamp production, paper sheets were hand-fed. But a more automated method was in place by the 1880s.
Btw, there is a terrific thread in a different category that explains this process very well: http://goscf.com/t/11260#11260