How can I tell what my puppy is?

I know this isn't a big deal, but I'm only curious. We just adopted our lab from someone who could no longer care for him. He's about 14 weeks old, I don't know where he was bred from or the pup parents. He looks like a chocolate and black color mixed - although not important. My question is more so about English show and American working type. I have read that there are temperament differences between the two. Can anyone answer this and also any kind of advice, helpful tips etc would be fantastic, too as we are new Lab owners! So excersize, ideal diet (other than food packaging recommendations - or stick to that?). I'm interested in it all! Thanks ahead of time guys! It's truly appreciated. I'll try to post a picture of him if I can.