Continental Currency Question?

Most likely, they made a stamp with their signature, which was used for each individual note. Alternately, perhaps they made one signature for the printing plates directly (though I'm not sure in what way it could've happened).
What they almost certainly didn't do was to ask someone else to sign it for them (as you seem to imply); it was definitely their hand involved at some point, but how far that involvement was removed from the actual note picture is hard to say.

That said, this early, it's possible (though fairly unlikely) that they did, in fact, sign each note individually.
Are the signatures identical (like completely identical) on different examples of the same type? If so (which I suspect to be the case), they were definitely made by some replicating method (not necessarily one mentioned above, though I can't think of other possibilities right now).

Just for the record: I do not actually know anything about continental currency (other than it being American paper money from sometime in the 18th century). All of the above is just some common-sense considerations, and can apply just as well to any other 18th century paper money, American or otherwise (and even to paper money from other centuries, though I don't think there's much of it known from the 17th, and I doubt anyone was still signing each individual note by the 19th).

Thanks for the info! I think I mis-spoke on this. The note is a 10 shilling note from 1771, so isn't Continental Currency. I know the note was issued in a series of 10,000 so that would mean 10,000 signatures. It very well could be a stamp, the signatures look the same as some other copies of this note, but slightly different in others. I'll probably still go for it as it's not overly expensive, would just be really cool to get live signatures on this as the signatures are well known Patriots in my state.