You want to put a faux bolt in there?
I think that having the hop up visible just behind the dust cover is good enough. Unless your dust cover pops open while firing in which case the faux bolt might prevent that little bit of sand/dust getting in.
My gun has just the dust cover and all I need to do is pull it down to change the hop up.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE