Miko was 1lb 2oz or 1lb 6oz (one of those two) when we got him at 12 weeks and he is now 11 lbs, and NOT one single ounce overweight. He's just the right size for his body size. Of course he was sick with coccidia, hypoglycemia, and a bunch of other stuff, the breeder ended up being a puppmill broker, but the point is that you can never know for sure...
It seems like your baby will be around 4-5lbs, but it's hard to tell.
Looking at the parents and past litters of those parents can give you a better idea
