A week or two won't make that much of a difference, now a month or two, and you are looking at potential problems, and corrective work to try and correct those problems. Sometimes, as is the case with my mare, you get relatively lucky, and in spite of the crappy long feet, they come out okay, but more often, you'll end up with potentially twisted legs, incorrect angles, hip and back issues from trying to compensate for the feet. My mare moved around a LOT which I think helped her trim her own feet down some, so they weren't as bad as they could have been if she had been stuck in a small stall where she didn't move. She does have a few issues with her hind feet, as she spent a lot of time spinning in circles, so the inside walls are pretty straight, while the outside flares easily and dishes, but the structure of her legs is sound.
If you can, if you aren't bringing her home soon, I would talk with the owner, and see about getting a farrier out, if possible, offer to be there to hold her or something, and see if you can get her worked on. Good luck. Post pics, we wanna see the horse lol.