A CU 22 will be shorter than a CU24 because the scale length is the same, but the neck is longer to allow the added two frets, which moves the bridge "up" the body, therefore increasing the whole guitar length.
So no, not all PRSi are the same length, even roughly.
The shortest guitar is probably a 24.5" scale length 22 fretter, like an SE ZM or Santana. (Note the Core Santana is a 24 fret model, so wil be longer).
It would be a nice spec to publish, but it does seem to be not presented anywhere official.
If I have the wherewithal one day, I may measure total length of several models, but not tonight, Josephine...