stmontgo, FYI -
Setting the NLS_DATE_FORMAT does change the RMAN timestamps that I was looking for. I had messed up my profile options..nevermind.

oracle@dwdev01[/export/home/oracle/rman/DWDEV] export NLS_DATE_FORMAT='DD-mon-YYYY HH24:MI:SS'

RMAN> run { execute script dwdev_periodic_arch_bkup; }

executing script: dwdev_periodic_arch_bkup

released channel: ORA_DISK_1
allocated channel: t1
channel t1: sid=18 devtype=SBT_TAPE
channel t1: Tivoli Data Protection for Oracle: version 5.2.0.0

Starting backup at 26-apr-2004 16:54:24

current log archived
channel t1: starting archive log backupset
channel t1: specifying archive log(s) in backup set
input archive log thread=1 sequence=57725 recid=599 stamp=524505111