I recently traded my Rev B for a Titan (in the US).
(That went extremely well, BTW; Roon staff were excellence itself!)
I was told that there’d be no RAM (for music storage, that is; the smaller SSD to contain RoonOS is there in all cases).
Certainly you (seem to) have no choice of how much installed RAM on this page in the store. Or, at least I can still see nowhere to select 4 or 8 GB etc.
But maybe my case was special.