I've got a spreadsheet of all of mine here (incl some of the ones I co-owned or held breeding rights to). Winnie (my first) was a bit of an outlyer due to the fact that girl "ate to live" (vs the normal lab that "lived to eat"). She was so thin as a puppy I had to put her on high octane food just to get the calories in her.
Most have been +/- 5# of the *4mos* weight. I asterisk that because 16 wks is not 4mos. 4 mos in Barry's case is in 2 days, which actually is 17.5 wks. When puppies gain 2-3 # on avg per week, that 10 days can make a difference.
And yes, it DOES depend on condition of the pup. Many show breeders around here have told me to "feed your puppy"... I personally like to raise mine w/ a smaller layer of reserve fat than others and before anyone jumps to conclusions, my own vet (who used to breed/show labs) has gone w/ another gal to evaluate litters for service work and has told me many were "obese" (her words, not mine).
I prefer to keep enough extra on my pups so when they have their little growth spurts, they aren't looking anorexic and also, in case of illness, they have a few days' reserve there to carry them thru if they don't eat well.