Indeed the Swiss bought militarized CJ jeeps from Willys, right from shortly after WW2, as did the Dutch Army, the Belgians, and a whole host of other nations.
Here are some details where the militarized CJ-5 differed from the M38A1:
Battery box in the cowl, Jeep stampings on cowl sides:
Rear tailgate:
View on the dash: hand brake under the dash to the left of the steering wheel; note small fuel filler:
Difficult to see, but front springs have only five leaves:
Rear springs have twelve leaves:
Chassis serial and engine numbers, year of manufacture: