As of a radio matrix dated 3/8/10 it's still county wide L-tac. What you are hearing on C-Tac-2 is dispatch traffic for the new County Services and County Parks Bureaus with no busy tone as is typical of most LASD dispatch channels.
As far as I know, unless you have something concrete, the following has not been changed;
DUE TO AN INCREASE IN THE NUMBER OF USERS REQUIRING COUNTY WIDE RADIO COVERAGE,
THE PURPOSE OF CERTAIN RADIO CHANNELS HAVE BEEN REVISED.
EFFECTIVE OCTOBER 1, 2009, THE "SCC ACCESS CHANNEL" WILL REMAIN THE SAME AND
"SUD" WILL EFFECTIVELY BECOME "COUNTY L-TAC".
THE SCC ACCESS CHANNEL HAS LONG BEEN UTILIZED AS A MEANS FOR NON-PATROL ASSIGNED
FIELD UNITS TO CONTACT SHERIFF'S COMMUNICATIONS FOR VARIOUS REASONS.
THIS CHANNEL IS ALSO UTILIZED BY OUTSIDE AGENCIES FOR THIS SAME PURPOSE.
THE SCC ACCESS CHANNEL WILL REMAIN AS IT IS TODAY, BUT WILL SEE AN INCREASE
IN USE AND WILL REMAIN "SCC ACCESS".
SPECIAL UNITS DISPATCH, OR SUD HAS BEEN USED FOR TACTICAL COMMUNICATIONS FOR
THOSE UNITS THAT DO NOT HAVE A TRADITIONAL L-TAC. THIS CHANNEL WILL BE
RENAMED "COUNTY L-TAC" AND WILL BE USED BY ANY COUNTY WIDE UNIT
NEEDING CAR TO CAR COMMUNICATION THAT IS NOT ASSIGNED TO A PATROL STATION L-TAC.