Approved H1B not stamped. Can I transfer it?

I got my H1B visa approved via a firm A with the approval date as 9th Oct 2013. Now they had no projects of my profile. I hence resigned. I do not have the i129 or the approval letter with me. I do have the Case no, and the print out of the approval screenshot from the USCIS website. I have now joined another firm B, which has lots of projects in the US. Can I use the same petition case no to transfer/ apply for new H1B anytime this year? What if the Firm A revokes it?

Just as a note, the Firm A was a startup and the Firm B is a Consulting Giant.