Got a 69 Rearveiw Mirror w/ Maplight, how replace blub?

[72c5]

Seems like a dumb question, but I cant figure out how to get the bulb holder out of the bottom of the mirror. Ths clear plastic lens pops right off but does not open a big enough opening to remove the bulb.

I had a 71 Skylark w/ a maplight; and on that mirror, the whole slider unit popped right out of the base.

On this mirror it feels like the old, brittle, plastic parts are gonna break if i try to pry the unit out of the mirror base.

On this 69 Chevelle mirror the bulb has a metal snap on diffuser that keeps the bulb from falling out the access hole with the lens popped off......

BTW for you Blazer guys, the mirror map light is great when the top is off.