Pro presently connects to 5 ultrapeers whereas LW free connects to 4 unless it's lucky. Correct me if I'm wrong here anybody. You also get the other small xtras with pro. eg: better chat options.
If you're not sure whether you dwnlded it or not, as a pro user you should have a personal update & dwnld page. You can always redwnld by checking your dwnld page see here (click on link) & type in your email. Whilst the diffs b/w Pro & free are not dramatic, consider it's not very much really & it's for a good cause. It's almost like a donation really. Imagine if there were no LW (went bust for financial reasons.)