Wow, I have never heard of something like that before hehe. How much was it? If it was a lot, I'd say hes going to try get away with the free code. If its little, I'd bet he'll pay eventually with that positive track record he has.
I don't think you'll be covered with this. I'm no expert in paypal disputes but a seller giving someone something before they paid is just not common, unconventional and not very believable. You didn't follow proper ebay protocol so I don't think this will work out in your favour if the buyer doesn't pay.
Then again, I'm no expert, I've only had 1 problem on ebay and it that case I was the buyer.
If he doesn't pay within a week, threaten negative feedback. I think that's all you can do really
Hope you get paid.