I have several of the nylon Hogue Monogrips going back to the 70s-80s. They have a silver colored crest on the right side. They nylon ones predated the rubber ones. I tried a rubber Monogrip when they were first introduced. Much prefer the nylon version. The stippled gripping surface on the nylon Monogrip is, for me, the best grip surface I have ever used. Great traction but still easy to maneuver if one wants/needs to slightly alter one's grip.
The plastic Safariland grips started out as Rogers grips, eventually being purchased by Safariland. They were extremely popular for duty as well as PPC competition. I liked both but preferred Rogers/Safariland slightly.
The Rogers/Safariland grips had a very narrow shelf or swell at the base. For barricade use this afforded more gripping surface for the thumb and forefinger of the weak hand at the barricades, thus greater stability. One has to look closely to see the difference. If one is familiar with the feel of different DA grips it is readily apparent.
Old habits die hard. I have a departmental commemorative S&W 586 revolver on display with custom S&W finger groove grips. All of my other DA revolvers wear either nylon Hogue Monogrip or Rogers/Safariland. On the belt or on the line my only priority is function, rather than looks.