I agree with Researcher, during that period, there were lots of transitional guns being made.
The grade stamps, engraving, and barrel composition varied.
I guess that it was related to what parts were available and shipping dates of completed guns.
Here is an example.... What grade are these 16's???

No grade stamp at all.
Now, the engraving. Both have Krupp barrels.

I've seen more than several other smallbores in the lower grades with Krupp barrels during this time frame.
I would not find your gun's stamping, engraving, and Krupp barrels to be unusual.
It would be interesting to see how close the serial number is in relation to these guns.
If anyone has ....#77 or 78, I might be interested.