Warbird Information Exchange

I have several indicators marked GE 321W, GE 321R. W designating white and R designating red. These are mechanical dimmers and I believe are original part numbers installed on P-51's and possibly others. Notably the 321CA (which I do not have but want!) CA designating "cloudy amber", is in the original parts catalog for the P-51's listed in the subject line. I desperately need sockets or bases
for these. I can't make out the actual part number for them in manuals online. Does anyone have a clue where I can get my hands on some? I've tried several modern versions and can't get anything to fit just right. Any help would be greatly appreciated. Thank you.