Blaster scopes

I was looking at the visual dictionary picture of fett the other day, and his scope is mounted by only one thing, like this:
But most people's scope's I've seen here are mounted with two mount things. Why is this? As far as I can tell, the visual dictionary fett is ROTJ, and that's what costume I'm doing, but I don't know why the gun would be different like that. What am I missing?

I think part of that picture was cut off or something. That scope is nothing like the one in the move or the archives.

That's only half of the scope.... it was "cut" in half during ROTJ

Ohh yea I almost forgot about that. I guess there was more than one prop made and one was cut. it must have been slightly reassembled or he is just holding it together for that picture then. The archive/MOM/AofSW etc all seem to have a complete one though.