I am looking at the 'UTG MNT-751' and 'UTG MNT-751L' front flip up sights made to mount to the gas block.

One review says that the low profile version (the one with the 'L') is required for gas blocks whose rail is the same height as the main rail.

Anyone confirm or know if the low profile version is the correct version? (I am assuming that gas blocks on other rifles are much lower.)

Thanks in advance!