Yes the LCAL fleet was very old, which is why the merger really helped CAL because all the new guppies that were delivered post merger (2010) wouldn't have happened without UALs cash on hand.

Plus parking all of CALs old 767s and getting new scabliners made the overall fleet newer.

UAL had those "old' 747's delivered as recently as 2001 and those "old" Airbus delivered as recently as 2005.

So the myth that one airline had an "old" fleet was a SLI slight of hand and it was shown that it didn't matter.