Hmmm.
Very interesting.
A couple thoughts for your consideration.
In my experience very early pieces did not utilize generic crossguards so the combination of a tapered tang and a generic crossguard is rarely seen. Some of you guys who have dealt with more armies may have. Early tapered tang makers in my experience bought crossguards from other makers, more often than not from Pack.
It would be interesting to see the inside of the grip to see if it's freshly hogged out to accept that tang...
Ok having said all that I am not discounting this maker mark. Are the scratches right through the maker mark I suspect they are with no evidence of the maker mark being applied after the scratches. It would be a heck of a lot of work to apply that maker mark to one blade then scratch it all up like that. For what? An extra 100 or $200 on the collector market? Sounds like this was obtained at an estate sale where no one stood to profit from an unusual maker mark. My gut says this blade is ok. You may have a winner here but there are many mare knowledgeable folks reading here. Hopefully they will share a pearl....