Like yesterday’s Bryce menu, this one doesn’t have actual menus printed on the inside. The cover photo also has a large, nearly uncolored area, allowing the greyscale of the original black-and-white photo to represent the “Great White Throne,” a rock formation in the park. So it is probably the same vintage as the Bryce blank, whenever that was.
The Union Pacific featured Zion in even more ads than Bryce, probably because it was a bit more accessible and thus received more visitors each year. Zion, which dates back to 1919, received slightly more than 33,000 visitors in 1929, or 3,000 more than Bryce. By 2020, Zion attracted nearly 3.0 million visitors, more than twice as many as Bryce.
Above is an ad from the 1926 National Geographic that shows the Great White Throne in color. The use of color was rare in those days, and an identical ad but in black-and-white appeared in several other magazines that year.
The above ad, from the May 20, 1946 issue of The New Yorker, uses an illustration that is a little more abstract than the one in the 1926 advertisement.