tennmogger is correct about that mount being intended for the MX-6707 and other bolt-compatible bases. That style of mount is used on many trucks, including deuces. It's commonly called the "sugar scoop mount", though that term doesn't appear in TMs. It's a different style of mount than the ones mounted on the sides of many M1009 trucks, but it holds the exact same antennas.
Even tied down, any of the whips/bases that will fit that mount will add a few feet of height to the truck, and tying the antenna down really far is bad from the base spring... not that it matters much if it's just for looks and it'll always be tied down.
Even the old (going back to WW2) AB-15 bases can be installed on that mount with a suitable adapter plate. I got a NOS late-1980s radio installation kit for my HMMWV which included an AB-15 and the adapter plate instead of the newer AB-558, because there were so many spare AB-15 bases in the system that they were still using them for new installations 40+ years after they went into service! The adapter plate is nothing more than a round steel plate with four bolt holes for attachment to a mount with the MX-6707 bolt pattern, and a center hole of the right diameter for the AB-15 base.
If you put an antenna on it, do make sure that you tie it down and are aware of the total vehicle height. A friend told me of an M-151 owner who pulled into a gas station with his MX-6707/AS-1729 up, and he took out a row of fluorescent light tubes on the roof over the pumps.
The antenna would be even taller mounted up on your contact maint. box.
