Backup & Recovery :: Querying V$archived_logs To Backup ARC Files?

When we backup .arc files we issue a RMAN command similiar to this:

KEEP_ARCHIVE_HOURS=2
rman <<EOT
connect target ....
connect catalog ...
sql "alter system archive log current";

[code]....

The problem is at times there may not be any archive files that meet this criteria and RMAN throws an error

RMAN-06004: ORACLE error from recovery catalog database: RMAN-20242: specification does not match any archived log in the recovery catalog

I was considering using the following code to see if there are any available .arc files that meet the backup criteria.

set pagesize 0 feedback off verify off heading off echo off;
select count(1) from v$archived_log where
COMPLETION_TIME < sysdate-$KEEP_ARCHIVE_HOURS/24
and backup_count = 0 and name is not null;

While testing on several systems, I found that the above-mentioned query picked up some redo-logs (*.rdo) I can only assume that these redo logs were used for a DB recovery.

/u05/oradata/dmartdev/redo_01a.rdo120724-JUL-1125-SEP-11
/u15/oradata/dmartdev/redo_01b.rdo120724-JUL-1125-SEP-11
/u06/oradata/dmartdev/redo_02a.rdo120824-JUL-1125-SEP-11
/u16/oradata/dmartdev/redo_02b.rdo120824-JUL-1125-SEP-11
/u07/oradata/dmartdev/redo_03a.rdo120324-JUL-1125-SEP-11

[code]....

I have a few questions:

1) Is my assumtion correct about the .rdo files in the v$archived_logs table

2) I would hate to add special logic and look for something like name substr(name, *.arc) (pardon the syntax). Therefore, is there a way to get rid of these *.rdo files?