about to adopt a yellow lab from humane society

Question
I haven't seen him, I am told he is approx 6 months old, in pics he looks big. Previous owners gave him up to live in house trailer park.  What are some things I should be concerned with, any info would help.  He is 5 hours away, I cannot just drive down to have a look, if I go, I'll take him....I'm told hee has been house trained, trained to retrieve, sit, stay, and lay.  I am told he is good with children and other dogs.....Thank you!

Answer
Apply the criteria I have been taught for possible dogs to be donated as dog guides.  

Look
for dogs that want your attention, but are not going wild. Leave the ones that
retreat to the back of their cage.  Look at their teeth.  Look for ones that
still show a 3 lobed, clove like pattern on the front ones.  Leave the ones
that fight letting you look at their teeth too much.  If the points are worn
off the teeth, it is an older dog that may break your heart by dying too soon.
Pinch the web between its toes.  It hurts.  It is OK for the dog to pull away
or whine, but it shouldn't growl, snap or show its teeth.    Since the shelter likely will kill most of the
dogs, you may as well pick out a nice one.

And thank you for considering adoption.  Come back with any questions that come up.