Correct just the mount is different like on the 67-72 style. BUT they don't make an over the counter rubber 360/340 mount. You can use a 318 mount with some spacers and all will be fine. I've seen picture of that setup.
I fished a 360 mount out of the junkyard and put/welded in a rubber isolator that you can buy separate. Buy the other 318 pre assembled with the mount and isolator together. Hardly any more money, not worth the hassle.