Be careful, those little white taps on the side (Optronics model) may snap when pushed in from being brittle. I replaced a bulb a few weeks ago in the right one, and the white tab snapped off. I was able to place the red lens cover on and then I used clear silicone to hold it in place. Quite effectively too!
Today, went to change the left bulb and didn't snap a white tab this time, the end of the red lens broke off.
Too much sun....
So, I have decided to replace them with the Optronics LED replacements that are identical size and have the same mounting holes.