I don't know if they were new boobs. I think it might have just been one of those push-up bra kind of deals, combined with the low-cut dress. They were definitely the first thing your eyes were drawn to, that's for damn sure.
Here. I found a picture, supposedly from her prom.
I think there is enough boobage there so that a push-up bra and the low-cut dress she was wearing to, in tandem, could possibly create the look she was sportin' last night.
I'm not sure though. Looks like I'm going to have to dig deep to solve this mystery...