I wish I had a little more patience to wait for your response - I went ahead and got 1 point in pickpocket, already had 2 in lockpick. I guess it worked out, since I got a point in lockpick in return.
Your repone did help though - I was stuck in the castle dungeon area (cells & Executioner) and couldn't figure out how to proceed - since there was no way from that point. Sneaky game design!
thnx
MikeK