I was thinking about a situation where someone accidentally reveals a copper from their starting hand while shuffling their deck or discovers that they only have 9 cards in their starting deck (and they are certain they put the required 3 Estates in).
If they added a copper from the supply to their first hand, and drew 4 more of the remaining 9 cards, would their odds of getting a 5:2 or 2:5 hand versus a 4:3 or 3:4 hand be any different than if they drew a normal 5 card starting hand from a normal 10 card deck? (I realize that a 5:2 hand is slightly different than a 2:5 hand, in that it allows you to change your possible 2:5 coin buy after an opponents first purchase. The thing I am wondering though is if it changes the chances of getting a 5:2 split versus the more likely 4:3 split).