When the vase fell the first time - it was lying open. But when the vase fell the 2nd time - it was wrapped in a gift paper. There has to be a difference in breakage pattern when an item (vase) falls when lying open & when in a package.
Stick to your choice of Door#2. Probability of finding $1000 is 50% on each door. Sticking to the choice will also reap in additional $300. No matter where the booty is - you will win $300 (min) in either case