At a year and a few months old Tucker is around 9/10 pounds, (havent wieghed him lately, but dont think he has gained) anyways at 8/9 weeks he was 2.5 pounds and when I had him spayed at 4.5 months old he was 5 pounds. If your pup is already 4/5 pounds then he will probably 12 pounds or more. There is no way that he will stay under 7 pounds. My "little" guy came from parents that were 4 pounds a peice so you cant really go by that either..
.. They come in all shape and sizes and even though your pup may get over 12 pounds they are still considered small..
Im sure he is cute as a button..