Locktiteing a dummy hider on will probably be fine (as long as you don't do anything stupid) or just cut the hider off to leave the sight.
Don't quote me but I'm pretty shure that because those treads are used to hold on the front sight and so long as you don't have any muzzle device on it could be argued that because those treads do something other than just hold a flash hider it should be fine to leave them on
Now I know for certain that becaus a bare reciver can't be an assault weapon by itself it is fine to buy and own so if I was you I'd buy em up
Don't quote me but I'm pretty shure that because those treads are used to hold on the front sight and so long as you don't have any muzzle device on it could be argued that because those treads do something other than just hold a flash hider it should be fine to leave them on
Now I know for certain that becaus a bare reciver can't be an assault weapon by itself it is fine to buy and own so if I was you I'd buy em up