64bit versions of PCLinuxOS are not officially released yet.
Only pre-release (test) versions are being made available in the servers, for testing purposes only (they are not officially supported).
If you didn't use one of the 64bit test isos for your installation, then most certainly you are on 32bit.
You can also type uname -m in the terminal.
If you are on 32bit you will see i686
If you are on 64bit you will see x86_x64