It is normal. Simply use a larger drill bit and drill the gimbal mount for the unit then you will be able to finish the process of bolting it to the RamMount.
From Sales to Installation Services and Education/Instructional Trips
it's all coming together and we have you covered @ Shut-Up-And-Fish LLC
for all your Humminbird, Minn Kota & Motorguide needs
We also stock the LiftSaver TM Bracket 972 822 9285