forward assist and dust cover are not neccessary on a properly working ar15. my colt sp1 i bought back in the 80's has no forward assist and i dont remember if i ever bothered using the dust cover. ive prolly shot close to 100k through and i dont think its ever had a fail to fire and ive long since replaced the second barrel.
unless you realllllly just gotta have em i dont think they are neccessary at all.
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." — L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...
"I crapped my pants to avoid the draft!!" -Ted Nugent