No, not the same.
The bearing diameters on the spindles are different between 52 and 53. See this bearing info https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=604816#Post604816
That said the mounting ears on the spindle for the backing plate may or may not be different, and that's what matters I expect.

You can probably get around any possible troubles by using the later model spindles and hubs if necessary on your older axle beam, the king pin diameter/kit should be the same.

Ask the seller any questions but even if you try it out on your own I think it could be made to work if it's not a direct bolt on to the older axle.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-