(Johann Georg?) Gutruf cup

I have a cup marked on the bottom Gutruf and under that 501 which looks like a model number for the cup and then what looks like a column or pedestal and then 800 followed by a crescent moon and then a crown. I’m sorry the crown came out a bit fuzzy in the photo. Can anyone give me any info on when this may have been made or any other information. It seems Gutruf joined up with Brahmfeld and their hallmark was 1842 to the present, so I’m guessing t his is pre 1842?
Thanks,
DougL

The moon and crown mark was introduced in 1886 and the mark is that of Koch & Bergfeld of Bremen (see here). Gutruf was probably the retailer.

Phil

Thank you so much, Phil,
I just went to the website of Koch & Bergfield, and I see those hallmarks. The date for that particular hallmark set says

about 1884
The next progression of hallmarks on their website shows as
and seem to indicate they are
from 1980
That’s a big time frame from around 1884 to 1980, so I’m wondering how one would know it it means about 1884 or from about 1884 until from about 1980. If that’s the best we’ve got, it would seem to indicate that we can only pinpoint it down to about a 100 year period from about 1884 to about 1980.
Sincerely,
Doug

Maybe K&B have records which would pin down the 501 number to a specific time period?