Suzkat, they were sand cast like your swage block. four main parts the rigid post, the front jaw, and the screw, and ball nut which were threaded. also the mounting plate was also cast. The handle was round stock, the rest is flat stock stamping. They've been made that way back to the 18th century or earlier. The swage was probably stone ground on the flats, where as the vise was at most file finished to get rid of the roughness. also the jaws may have faces riveted or pinned on. By the way another good find. You are definitely getting some lucky finds. Note the wood block under the post, very common to be mounted on a stump chunk
Bill