IMHO, every dog is a crap shoot....sometimes you get lucky and get a mutt that would put some field trial dogs to shame; other times you have field trial prospects from good stock that couldn't find thier food bowl if it was coverd. These are the extremes.
You say "she looks to be pure lab"; highly doubtful. As far as being a lab mix, that is probably just a guess as well. My old boss got a 'cockapoo' puppy from the humane society....that thing grew up to be 70+ pounds of mutt that looked like a bluetick coonhound!
Hardly the 'lapdog' that his wife wanted.
YOu say you can adopt her for $94; for a couple of hundred more (maybe less) you can get a lab of decent breeding, and your odds go up consideralby as far as having a 'hunter' go.
Think about this for a moment (just playing devil's advocate): You adopt the pup, she becomes the hunting dog you want, and everything works out hunkydory.
.....but what if she has no interest in birds, retrieving, or runs at the sound of a gun? The kids are now attached, so getting rid of her will be hard; your wife probably won't let you have another "big dog' in the house, so getting your lab now is no longer an option, and there is the monetary expense of keeping a second dog (shots/food/licenses) that doesn't 'earn it's keep'.
Sorry if I muddied the waters even more.....just realize what you could potentially be getting yourself into. Good luck with your choice.
(BTW: I believe in training a dog from 8 weeks of age on, and not just to house break them, either!)