Yes, that's a super mojave. The grey is normal for those and will stay that way it's entire life. A super mojave isn't a pure white snake - if you're wanting that, go with a lesser mojave.
The pictures you posted are hard to judge size from. How much does it weigh? Males can still be pretty girthy if they're fed a lot. It's not uncommon for a 2 year old male to be 1200 grams.
You won't know if it's male or female until you have somebody with experience sex it for you.
Sent from my SAMSUNG-SM-N920A using Tapatalk