I have a twin to this one..what maker? This style of drum was made for many years and in other colours such as green, yours looks period..i think these were even made after the war, but ill defer that to others with more knowledge on the subject
I don't think you will ever be able to prove that this was a HJ drum.
These snare drums were made throughout the early years of the 20C with different coloured triangles.
Nice to see that it still has the two holed hook that the belt loop attaches to.
The paint seems as though it may have been refreshed in the recent past.
Here is a link to one that dates from the late 19C
Side Drum | German | The Metropolitan Museum of Art
Looks like an original one but as said it's almost impossible to be sure. I agree with Saladin: looks like it may have been repainted. Nice drum