Prefacing this with the disclaimer that KCG is not fully confident in this identification. The original mould appears to have been for the Custard Cup Saucer, and this plate is consistent with other U.S. Glass plates within the Dubonnet pattern. We have what we believe are both hand pressed and machine pressed examples, and we classified this as machine pressed based on the foot: this example has a foot depth of 1/16" and has a sharp edge to it, whereas the hand pressed has a foot depth of ~1/8" and has a very smooth and polished feel.
We also noted that on the items we believe are hand pressed, the staining is also hand painted, extends into the sawtooth band, and has a consistent coloring, whereas the machine pressed plates have the normal circular stain, and vary often dramatically in color and quality.