I recognize, as aviators, you guys may have a slightly different practice for reserve units dedicated to aviators. My unit represents CNE CNA 6th fleet, which is a mashup of all types of designators and the CO has typically been a 13XX type and there a bunch of 13XX in my unit. If he used an internal list, it wasn't visible to me. From what I could tell, it was done strictly by the RMP list, with callups handled by the NOSC.
My comment was directed towards the post-RMP era. I completely get what you're saying during the RMP era. There was no need for an internal list because there was already an external one (as you mentioned).