You have to take a minimum of 3 Wolf Guard. If they don't have Power Fists I'd give them Meltabombs at least.
I'd also give Long Fangs
TLLC Razorbacks instead of Las/
Plas. The Las/
Plas makes more sense on the Grey Hunters as they are more aggressive, but not sure you really need it with Assault Cannons. I'd prefer to take my chances with the Rending hits and keep the 4 shots/turn versus dropping down to one or two shots with AP2. Also the
TLLC will help with popping the Necron's AV13...
3 Long Fangs is a bit excessive for 1250. Mainly because I'd prefer to spend more points on wargear. And while 3 Troops are usually enough at 1250, you could squeeze in a 4th Grey Hunter pack instead.
Maybe something like this:
Of course, I tend to rely on my Grey Hunters to do most of the heavy lifting. With your original list you're running a gunline almost and you are relying on your Long Fangs and Razorbacks.