I am not very educated on Yorkies, I have only had mine since the 1st of November, mine has a pedigree, and now that I have one with a pedigree I really dont see why I would need one, I am not going to show her or breed her or anything, I just want to love her!!!!
She is healthy as can be too. She does have LP a little bit, which I told my breeder and she checked her sister and thinks she may have it as well and is going to take her in to get her checked out. She was very upset to learn this from me.
So I guess my point is that it depends on your plans with your puppy!
I got my other two animals from the pound when they were a few months old (6 year old Border Collie/Lab and 7 Year old cat) they both came from bad homes with way to many animals not being taken care of and we have had no health problems etc.... so this lady might just love the puppies and want to let others be able to afford them, who knows. I actually thought that might have been a possibility for me and my little girl but as I thought about it more I couldn't handle my puppy possibly not making it through birth and loosing a little new born puppy, NO WAY! I would cry for days! So I leave it up to the others who can handle that kind of stuff.
So if you love the dog and he is being cared for in a good home and she is concerned about him going to a good place I would say it should be ok. Maybe ask her to put some kind of health cert. in writing so that you can have her help if something major comes up. Personally, I think you can't guarantee on any animal if its going to be ok, its like getting a husband or having your kids and saying wait this one has asthma can I put her back!
This is just my 2 cents, may not mean much and thats ok, but you asked for opinions!
Best luck with your new pup wherever he/she may come from!