Does the 1924 catalog list the calibers available in takedown?

No, it just mentiones the take down feature as an option, just as the scoped option.
According to Jon Speed's books, production of the short intermediate, slant mgazine rifles in .303 ended about 1903 after a total production of less than 50 rifles, according to Paul Roberts. At least one example had the take-down feature.
The last stepped ring receiver, slant magazine rifle in .400-350 was sold in 1910. So both were not offered any more in the 1924 catalog. The 1924 catalog still illustrates the Model No.4, 350 Magnum rifle with such a stepped ring action. The "Rigby's New Telescope Sight" option pic shows a short intermediate, slant box action with a pre-WW1 German Goerz scope, but old catalog pics never should be taken to be exact. Each catalog picture then started with an expensive hand engraved cut. So such illustrations were used over and over, as long as any reasonable resemblance was given. This applies not only to Rigby, but to most old catalogs too.

Are takedown prices higher?

That catalog does not give any price itself, just a sentence: ""FOR Price see separate PRICE SHEET", which I do not have. I understand the take downs and the scoped rifles being extra cost options.