With regards to the flashhider...
I wish, they´d have used an actual muzzle, which would have made it somewhat easier for us to identify it.
Anyway...I don´t think, that the "thing" they used here does even have any actual "cooling" holes besides of the one at the front.
Take a look at the following two pics...
The muzzle with direct light hitting it...IF there were any holes, they´d catch/ break the light and we´d see them here.
Now check out the same muzzle with indirect lighting and BAM, there are cooling holes.
BUT they´re somewhat irregular and even differently sized, right!?
My theory is, that whatever the prop dept used, the cooling holes were simply PAINTED on, just like on the Hoth DL44. Back then I was -one of- the first, who followed that approach. Prove me wrong with regards to the bunker blaster

*lol*
p.s.:
The longer I look at the pics, the more I think that the muzzle was cobbled together from different parts. The front end looks like an old hose coupling. Something like this:
