These are all the ads I could find on Saturday Evening Posts published between January 1948 and December 1949. Again, it seems Willys-Overland’s advertising was an exercise in experimentation. Some notes:

1. City-And-City Campaign: The first obvious item is that Willys-Overland ran its wagon city-and-city campaign in 1948, but did not run all the ads produced in the Saturday Evening Posts (as documented here). Collier’s Magazine also got a few as did Life Magazine.
2. W-O Graphic: In a November 11, 1946 (see 1946-1947 ads here), ad Willys-Overland used script for Willys Overland Motors. In December 21, 1946, the script was accompanied by the graphical representation of Willys-Overland in the form of an yellow “O”, colored red on the inside, with a yellow “W” atop that design.
   
   The scipt disappeared in January on 1947, leaving only the W-O logo. In February and March of 1947 the W-O logo was absent from ads, but then in April of 1947 it made a brief return, before disappearing again.
   
   In Febrary of 1948, the W-O logo reappeared, this time with the ‘Jeep’ logo hovering above it. That combo was used through May of 1948.
   
   In June of 1948, the ‘Jeep’ was dropped in favor of just the W-O logo. By July, the W-O logo disappeared for 1948 and 1949.
3. CJ-2A Barely Advertised: Trucks and wagons dominate the advertising. There’s only one ad in two years for the CJ-2A and none for the CJ-3A. One reason for this is that Willys-Overland expanded their advertising to other magazines. The Farming magazines (Farm Journal, Country Gentleman, and others) were more CJ-ad oriented.
4. ‘Jeep’ Product Badge: Through 1948 and most of 1949 Willys-Overland was advertising ‘Jeep’ Trucks and ‘Jeep’ Station Wagons. However, in late 1949 the company began a switch to WILLYS ‘Jeep’ Station Wagons (see October 15, 1949 ad), then the ‘Jeep’ name was relegated in December 1949 to a small (new) badge, while WILLYS became the more prominent branding once again. Here’s how the badge looked.
   
   In January of 1950, the company shortened WILLYS ‘Jeep’ Station Wagons to Willys Station Wagons, dropping the ‘Jeep’ entirely.
   

   January 07, 1950 Willys -Overland ad in the Sat Evening Post, page 86. Note the use of the ‘Jeep’ badge and the return of WILLYS as the primary brand.

5. From ‘Jeep’ to WILLYS: After February 1950, Willys-Overland dropped the ‘Jeep’ badge and the ‘Jeep’ branding of the wagon as a ‘Jeep’. Instead, the company went full WILLYS branding, as seen in the September ad below. This seems incredibly strange, given the company had finally won the Trademark for JEEP that year  (June 13, 1950 Awarded JEEP registered trademark).
   

   September 23, 1950, Willys-Overland ad in the Sat evening Post, page 57. Note that ‘Jeep’ has disappeared completely from the advertising.

   Why did Willys-Overland drop ‘Jeep’? I have no idea. But, it’s no wonder the average person is/was confused about whether a wagon is a ‘Jeep’ wagon or a Willys wagon!

6. In October of 1946, Willys-Overland introduced the phrase, “Makers of America’s Most Useful Vehicles” within its ads. That phrase would accompany ads into the 1950s. However, in December of 1949, Willys-Overland introduced a new phrase, “World’s Largest Maker of 4-Wheel-Drive Vehicles”. This phrase was only used once in 1949, but a variation of that phrase would eventually grace Willys-Overland ads (or Willys Motors) in the form of  “World’s largest manufacturer of 4-Wheel-Drive Vehicles”. I don’t have dates for when the former was dropped and the latter adopted … yet.

Below are the 1948-1949 ads from the Saturday Evening Journal:

UPDATE: Maury pointed out that a porcelain sign of this badge sold in 2017 (see bottom).

In the April of 1946 issue of the Saturday Evening Post (same month in Colliers, too), Willys-Overland introduced a new advertising badge for the Willys engine.

As you can see in the introduction ad (A New Chapter), it was matched with the announcement of the Willys-Overland Jeep Station Wagon, though the ad hides the wagon in anticipation of its summer of 1946 launch.

The badge made a second appearance within the release-announcement of the station wagon in the August 18, 1946, issue of the Saturday Evening Post.

The next month, in September of 1946, the badge appears for a third time, again associated with the wagon.

As quickly as the badge appeared, it disappeared with the same speed. For the October 1946 ad, which included a wagon in it, the Saturday Evening Post seemingly replaced the engine badge with a smaller badge, one with a “W” over the “O”. It’s the earliest jeep ad I can find with that badge (if anyone knows of another, earlier ad, please let me know).

At some point, there was a porcelain version of the sign. One sold on eBay in 2017: