Ah, if only you had asked last week when I had my radio out!
But it's really that easy as I described. If you remove the radio you can unscrew the HVAC control and it drops down with plenty of room and the flap is right there. Those little bulb holders just turn a quarter turn clockwise and come out. Then the bulb is just held into the holder by its own folded over wires. Unlike an LED you can't put them in backwards.
https://www.nicoclub.com/archives/cl...placement.html
Speaking of LEDs I wouldn't try using one in there because the way the light pipes inside work to spread the illumination across all the buttons really depends on having the 360 degree distribution of an incandescent filament.