I have a Fedora Core 3 sever setup with a hosting company.

If I SSH into the server is there a command to see if selinux was installed?

I'm not sure, but maybe some of these commands will help:

This checks the name for every RPM installed to see if any is similar to "selinux":

[mirandam@portia ~]$ rpm -qa | grep selinux
libselinux-1.17.14-1
selinux-policy-targeted-1.17.30-2.19
libselinux-devel-1.17.14-1

This checks the last bootup log to see if any parts of SELinux were loaded or initialized:

[mirandam@portia ~]$ dmesg | grep SELinux
SELinux: Initializing.
SELinux: Starting in permissive mode
SELinux: Registering netfilter hooks
SELinux: Disabled at runtime.
SELinux: Unregistering netfilter hooks

This checks if the kernel which is loaded had selinux enabled in it. This command may not work for you, if there are NO 'config-2.6.xxxx' files in /boot.

[mirandam@portia ~]$ cat /boot/config-`uname -r` | grep SELINUX
CONFIG_SECURITY_SELINUX=y
CONFIG_SECURITY_SELINUX_BOOTPARAM=y
CONFIG_SECURITY_SELINUX_BOOTPARAM_VALUE=1
CONFIG_SECURITY_SELINUX_DISABLE=y
CONFIG_SECURITY_SELINUX_DEVELOP=y
# CONFIG_SECURITY_SELINUX_MLS is not set

Thank you those commands really helped!