Some small additional tweaks, namely drilling out the holes under the folding stock and the slot on its side, and fitting the magazine with a small "ball" and the writing "OFF ->", as seen on original magazines.
Here an original magazine, picture lent from the great site http://sterlingblasterconversion.blogspot.com
Here's mine:
The holes under the foldingstock:
I think these details go a long way to make the blaster look even better, and they're really easy to do and completely free.
DO it!