18th.C French?

i’m back again with the same post - had another peek at the silver goblet and
realized the mark appears to be an oak leaf but what i thought was a letter x is more likely to be a number 4 to its lower right.

i cannot yet get a picture of it (yet) but it is reported as being French 18th C. but i cannot find any references to French marks this old. Anyone know if this even remotely rings true? Will try and get a pic.