That's definitely a NW. It looks like a healthy little albino.

As for over feeding, you should probably feed him 3-4 head sized worm chunks every other day, it's really easy to over stuff a baby, and it can be dangerous if done too much. Their muscles aren't fully developed, so they have a harder time swallowing and digesting food. They also have less stomach bacteria than, say, an adult wild caught garter snake. Letting them eat worms that have the soil still in them is a good way of increasing the gut flora.

I'm very glad he's doing so well for you! I hope that he brings your godson a lot of joy for many years! Don't be afraid to ask any questions you may have, we're always willing to help someone in need. And, considering albino northwesterns are quite rare, we're all interested in seeing lots of pictures of him! He's one of the first albinos that I've found extremely cute... I'm pretty big on the northwestern garters, though