There's a blatant issue with the universe naming thing, and it's that as time goes on, countless more Rick and Mortys are from C-137 because diverging realities should be being created at all instances. At this point there should be a near infinite amount of Ricks that can say they were from C-137.
Also, is it ever explained why there aren't an infinite amount of Councils of Ricks? As soon as its established it would also branch out tons of universes with versions of the Citadel, yet when "our" Rick destroys it, we are supposed to assume it's gone from all realities? Realistically it should still exist in countless other dimensions, unless there's some specific reason it's not in other universes.
I'm feeling that's what the "central finite curve" concept is meant to deal with. It gave me the impression that the Council arbitrarily filters out realities to focus attentions on a finite - but still incredibly large - sample of different realities. Conceivably, any branching of a given reality would in some way be detectable as a new, separate reality with its own sub designation (ie C-137a1, etc). Perhaps the central finite curve only includes realities designated as primary branches from a common point, and all the infinite branchings from each of those prime realities are somehow filtered out. Maybe the portal gun can only hold so many entries so the Ricks had to all agree on a specific subset of prime realities.
Was the Citadel of Ricks actually destroyed? It looked relatively intact to me - damaged and infiltrated by federation guards and criminals, but not completely destroyed? Conceivably it might just be replaced by an alternate, or maybe they at least find new Ricks with identical hairstyles to replace the dead Councilmen.
What now bothers me is whether or not our Rick would still be classified as being from C-137 at all after transferring into a new Rick body? Is that defined by the pattern of his mind or the dimensional frequency of his physical body?
I'm sure this has been discussed before, but was our Rick ever really from C-137 originally anyway? The casual way he jumped ship from Cronenberg earth implied he'd already bailed on earths before (and in Pickle Rick he refers to the first Beth as "one of" his infinite daughters, not "my original" daughter). I assume our Morty is definitely from C137 since he was able to use the portal gun to return to Cronenberg earth - if Rick had lied to him about his universe designation the gun would have taken him somewhere else (which frankly would have been a cool way to reveal that Rick had been lying about his universe of origin).