I have an older generation glock that I would like to replace the OEM sights with Truglow NS. The front does not have the small bolt but I think is pressed in - i think this is typical of the older glocks. Question - Are the replacement night sights universal as I think the new one I will need to install the small screw instead of the press fit? I have checked around youtube and other places and I'm not still not 100% sure although I'm about 90% sure these will work. my amazon cart ready to checkout. thanks in advance.