I could be mistaken but looking at that picture isnt mounting that torch on top o fhte beretta going to screw up the slide action, not to mention making the sights unusable.
I don't see that the torch is fixed to the top of the Beretta, it looks as if it has just been placed on top of it. The finish is different, so they are not "a set", I agree with Bouncer the "ribbon" that appears to say "police" looks very much like the "Wather" logo. You could not use the sights, as you correctly pointed out, it would change the balance of the gun, and as you say would render the use of the slide, if not impossible, then very difficult.