I can tell mine are still there.
How (all joking aside) ?
I see no differentiation if I visit a site that I have voted on or one that I haven't voted on.
If you are basing this on the categories flagged in the left pane ?
These are a collation of all votes and not just yours if you voted and the same I believe is correct if the reputation bar has a slider point set.
Unfortunately nothing has been said (as far as I can remember) on how the webrep works and how you know if you have already voted.