My 6 year old Chocolate Lab started getting grey hair the first time we studded him out at 2. That is what a wife and kids will get you (especially 10 kids)! He still acts like a kid though. I have never had such a calm tempered, intelligent dog in my life (this is about dog #10 since I was a kid). He is not neutered, I figured that is a decision for him to make. Since he doesn't have to make child support payments I can't see him making that type of decision .
Based on my expereince Chocolate Labs take longer than the other Labs to calm down. Although very intelligent it took mine about 3-4 years for mine to completely mellow out. Still good to go when they need to, just more come the rest of the time once they hit that point.
Congrats on the pup! I got a yellow lab last September. She is a ton of work! Lol I lost 7 chickens in 2 weeks! She is willing to learn and will be a good field dog. I hope... Good luck with your hound and have fun with it.
Hopefully here is a pic of my 4 year old chococlate in Shoal lake last fall......less ice! Of the six labs I've had she is the first chocolate and by the best I've had. [attachment=0:1vipsqv1]100_5759.JPG[/attachment:1vipsqv1]