Considering the number of rocks out there, I’m saying its a stretch to say for sure that this one came from Vesta. I would imagine a lot of the roids are pretty similar to one another.
Congratulations on your healthy skepticism. Naturally one thinks that ones own skepticism is healthier than the next fellow's, but the classification of these meteorite types has a long standing history, which I'm inclined to accept.
I'll tell you my pet peeve, which is actually sort of a multipart pet peeve, about this Vesta mission. The main part is that the DAWN MISSION page seems to be playing to the crowd, and disrespecting the knowledgable fans. There's a lot of politics behind this, and I'm loath to think a bad thought about the DAWN MISSION team, even if I do it once in a while. The second part is the lack of interest by the press. Consider this APOD, it's old stuff! What about all the amazing findings being released by the DAWN MISSION team? Oh yeah, refer to the first part of the pet peeve. "These pretty pictures are very meaningful to us actual scientists." Thank you sir, may I have another.