I just picked up a 556 Classic (SIG556301). It just has the tiny OEM flip up rear sight and the OEM front sight.

I'm torn between a diopter style rear or just an optic. Optic wise, I'd much prefer the look of the Sig red dot that the rifles originally came with. What model were those? Were they an older version of the Romeo 5?

From what little research I've done, I see that the stock sights sit lower than typical AR sights and therefor don't play well with most optics. True?

Thanks!