I actually like the two-fingered look. It’s reminiscent of the Toa Mata hand piece.
I don’t think this will be an issue; that rule is made more to prevent replicas of real-life weapons, not just the concept of “gun”. There have been plenty of blasters throughout Bionicle, at least one of which looks more like a “contemporary” weapon than this one.
Besides, I think it would be kind of ridiculous to ban a weapon that uses an official Lego blaster piece as-intended (more or less).