subscription-manager for RHEL < 5.7

Hello,
I have two RHEL 5.3 servers. Searching in the documentation I found that subscription-manager can be installed only for RHEL > 5.7, but If I do "yum install subscription-manager" on my 5.3, it finds the package. Can I install it? I am asking this because legacy RHN is dismissed now, as far as I understood.