Owner:Group on untarred program

[redhat at buglecreek.com]

I untared a program (chkrootkit) as root on a Redhat ES4 system and the
directory it created has the following owner and group:
 drwxr-xr-x  2   1000   1000  4096 
UID 1000 and GID 1000 does not exist on the system. After I compiled the
source the files in the directory have the following owner and group:
-r--r--r--  1 1000  1000   3365 Feb 21  2005 ACKNOWLEDGMENTS
-rwxr-xr-x  1 root root    2860 Sep  8 14:48 check_wtmpx
-r--r--r--  1 1000  1000   7195 Sep  6  2004 check_wtmpx.c
-rwxr-xr-x  1 root root    6144 Sep  8 14:48 chkdirs
-r--r--r--  1 1000  1000   6781 Sep  6  2004 chkdirs.c
-rwxr-xr-x  1 root root    6656 Sep  8 14:48 chklastlog
-r--r--r--  1 1000  1000   7730 Nov 16  2004 chklastlog.c
-rwxr-xr-x  1 root root    6768 Sep  8 14:48 chkproc
-r--r--r--  1 1000  1000   7613 Sep 13  2004 chkproc.c
-rw-r--r--  1 root root    4603 Sep  8 14:50 chkroot_09_08_05
-rwxr-xr-x  1 1000 wheel  71149 Feb 22  2005 chkrootkit
...

All executables are owned by root but the .c files are UID 1000.  Doing
a tar tzvf on the tar ball outputs:
drwxr-xr-x rn/               0 2005-02-22 07:06:40 chkrootkit-0.45/
-r--r--r-- rn/            8771 2004-09-06 13:24:56
chkrootkit-0.45/ifpromisc.c
-r--r--r-- rn/            1343 2004-09-06 13:24:56
chkrootkit-0.45/COPYRIGHT
-r--r--r-- rn/            6781 2004-09-06 13:24:56
chkrootkit-0.45/chkdirs.c
-r--r--r-- rn/            7195 2004-09-06 13:24:56
chkrootkit-0.45/check_wtmpx.c
-r--r--r-- rn/             571 2005-02-21 14:20:46
chkrootkit-0.45/chkrootkit.lsm
...

Why is the owner and group 1000 when that does not exist on the system?
I assume that the user and group ids were from the system that the tar
was made on?  Is this the case?  Also, what does the rn/ mean in the tar
file?

Thank You