The thought never occurred to me. With vacuum operated wipers that have manual operating handles as back-up, it kind of depends on when or how you turn them off (by the vacuum valve on the dash or stopping the engine). I guess for inspection you could use the manual handles to park them all on every jeep in a uniform manner but I've never heard of that kind of detail before or seen it in a tech manual. So long as they aren't parked in the center of the windshield I guess you can put them anywhere you want, both left, both right, both inboard, or both outboard?
I've never driven my jeep in the rain to use them, but from what I've heard about these vacuum wipers they're only slightly better than nothing. Mostly ornamental I think.

Plenty of Rain-X on the glass probably a good thing.
I park mine both inboard for looks, but they overlap one on top of the other (about 1/2-inch). I put the drivers blade on top because it usually lifts first when I turn them on.
Make it 4 cents with Mike's comment.

Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51
“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari