Building an Ar
 

I have a oracle 5.56 upper parts kit, I'm about to start puting everything together, my question is, if I wanted to change the gas block to a low profile one later, would I need a whole be gas tube, or will it fit the same?

AR gas tube differences are usually only tied to the length; (carbine, mid, rifle) A gas block change out shouldn't affect anything unless you have some otherwise exotic set up.