Well, it is a Registered Magnum for sure. If it is in top original condition and not modified, it is worth several thousand dollars. Even if somewhat worn looking and not fully original it is still worth quite a bit. If you search in the forum archives for "Registered Magnum" you will find many threads about these revolvers. They were essentially custom-produced revolvers built with an owner-specified barrel length and sighted in at the factory to the owner's preference (center hold vs. six o'clock hold, for example).
Two other RMs with serial and registration numbers in the vicinity of yours shipped in mid 1935, so your gun was probably shipped in that year too.
We'd love it if you could post some photos of this revolver.