Unfortunately, there will always be a time or two when they get something they shouldn't. But it sounds like he will be fine.
I have the same problem with Angel as you do with Rolo taking things. Although, now that he is older he is not so bad. But when I give the drop it command, 99% of the time he will drop it - in anticipation of getting a treat! It's not a great thing, but after all, it is kind of cute

- as long as they are not destructive and don't get over weight!