Old Porcelain Clock dated 1877

I bought this porcelain mantle clock from a German flea market and i was wondering if anyone knows its brand from the faded mark that is in the bottom. As you can see the mark is faded it shows as if there is an engraved serial number at the base of the mark 2 numbers are showing 5&7 along with a vague letter M in the middle of the mark and i do not know if the brand also includes an F in the beginning!!!!!! if anyone has seen this brand mark before i would be grateful.