okay so heres where im at. i just bought a DEL-TON stripped lower and a DEL-TON complete upper kit. its a flat top upper and a front A2 sight post. this is my first AR so im not sure what i really need? do i need to get a pair of sights? or do i just need a rear sight? also id like to be able to sometimes put a scope on it for some longer range... someone please send me in the right direction and possibly some suggestions for sights and scopes.