Acogs aren't 1-4, sounds more like an elcan spectre, but they can't change the reticle.
If it is, I'd probably avoid getting one, I'm yet to see one where the 1x setting is actually 1x and not 0.something.
There aren't any good full metal ones tbh. 1911s have very small mags which means efficiency on any metal ones is very weak.
KWA would be the best of the lot though.