Well, I really don't think it's a knock-off since it was my great-grandmother's, but it's a possibility I suppose. The differences, as I see them, are as follows:
1.) The "B.D." at the top is missing
2.) There is no "L" under the strange animal-appearing thing
3.) Directly above the animal thing is: D A G or something similar. Perhaps it is B & D? The ink is really rather smudged, the E in Limoges is fairly hard to make out as well. This actually may be an earlier piece by Bawo and Dotter, I think they were based in New York and started making limoges in 1860, the other mark doesn't date that early.
A similarity is the fact that they're both red, so this pretty much has me stumped!