Your thoughts please

first, No, I would not give you a copy OR a CAD file. I'd be surprised you even asked.
second, The Client doesn't OWN the map that the surveyor keeps on record. The client got it's copy when the project/contract was completed. If they didn't value it enough to hold onto it, it might tell you something about said client.

Contract with your client and prepare the ALTA for them. The old one would probably just get you in trouble anyway.