Is this the rail mount you were talking about?
----------
If Yes,
It doesn't have a rachet to allow you to lay down your antenna if you go under a low clearance bridge or while your towing. Plus (I think) you would have to drill a hole in your T-Top tubing to run the antenna cable through it and up through the mount to your antenna. I just recently added a second radio plus second antenna and all the rail mount ratcheting antenna mounts I've seen only fit 7/8"-1" pipes. Here's one from Cabelas for $29.99
So if you ever need to lay your antenna down you'll probably need to install a standard base mount and unfortunately drill holes.
Thanks, Fishing-Rod