Removable tail flap.

[arn2805]

The factory punch marks are different on the '17's and '18's. The marks on the '18's work for the removable tail flap. The marks on the '17's are not for the removable tail flap (see Norona's post above). On the '17's one has to measure, centre punch, and then drill. The '18's are drilled just where the marks are from the factory.

The marks on my 18 were off. I had to widen them out to get it to fit. Worth a double check if anyone goes to install the mounts.