Sadly no pics due to greasy hands. Yes I have a Dana 30 as well. Probably just a small difference in the casting that caused this. Best way to describe the area is on the edges of where the spiders gears for the center pin sit.
When you install this locker, just follow the instructions, they make it fairly clear what the steps are.
When you get to the part where you rotate the locker 90 degrees to install the outer springs and line up the hole for the center pin, you might have trouble rotating it. It shouldn't hit anything, but if it does then you know you need to pull out the die grinder.
I don't think this is an issue with the locker rather just inconsistencies in the casting of the carrier. I think I took off no more than 1/16" of material in an are about 1/4" high by 3/4" wide.