No I don't think you can ask them. You chose to take the dog, unless it was serious injuries, not just a check. Have you contacted the vets in the area? The owners may be looking at the shelter and you've claimed their dog. They would have had a few day stray hold.
If the owners come forward to claim her I think it's perfectly reasonable for you to ask them to compensate you for the fees you paid. Heck, I would even make that a condition for them to get to get her back. The owners would have had to pay that fee anyway to get her from the shelter, and if they aren't willing to shell over the fees to you then they probably wouldn't have paid the shelter to get her back, making them careless and irresponsible pet owners.
The pull fees are one thing but do not vet someone else's dog until you've exhausted all options and know you'll be keeping it. You've already re obtained the dog under false pretenses.