Definitely try! Although they may want to pull your credit again to verify that the collection was removed.
Good luck!
You can recon, but unless they pull a fresh copy, they won't see that the collection has been removed, and thus will probably stick by the decision. You will probably have to sacrifice another hard pull. Not sure on Citi's recon policies for denied apps really, as I have not heard too many positive stories, but it can't hurt to ask.