You would have qualified. Mobile homes were eligible. However, keep in mind that it was a 10% tax credit up to $8,000. That means the mobile home would have had to cost at least $80,000. So, if you were buying a mobile home for $30,000, then your tax credit would only have been $3,000.
But you had to be under contract by April 30.
On the other hand, mobile home sellers are a lot more flexible on price, generally, than "stick built" home sellers. If you're a good negotiator, or know one, you can save a huge amount by just negotiating the price down.
Hope that helps.