crt .5 mount-not tapped for threads??

[nitro28]

I got the rc-monster motor mount and only the 2 holes for the chassis screws were tapped for threads. The top 2 are just holes with no threads. Is this the way it is supposed to be or did they forget to tap them? Also when the diff is installed it doesn't sit perfectly square with the car, the spur is more forward on the motor side. Is that how it is supposed to sit?