So far in pulling No.1 hornets to 458's apart for my own needs, I have not found any real differences in the No.1 bare actions. I have heard about some extensions for the forearm being slightly different(barrel taper), but not run into that so far. Also have heard conversations about the early/late wood forend/receiver face fit to the receiver. Over the years the breechblock in some will be blued on top, some are white, etc; but the basic function is the same.
The ejector is a common part, other than the shape and reach of the hook for the specific caliber. So one could purchase a donor 458 Winchester No.1, tear it down, and put a hornet ejector in it.
Sometimes fitting is required for positive function with a new ejector, not to the hook, but to the sides of the base of ejector that goes over the major stud thru the action, ie left/right movements. Not a big deal at all.
One of the beauties of the no.1 action is its flexiblity, can become whatever you want, the only different part of the action is the ejector, which is a 10 buck thing and still sold to the users relatively easily.
The simple removal of the standard ejector and replacing with a magnum ejector will do what you want from the receiver's point of view, ie 473 to 532. The rest of it is up to you and your gunsmith. There is a fair amount of machine work to put an aftermarket barrel blank onto the action and function, the threading, chambering, ejector slot relief, the holes for the bases or quarterrib, and the sights if required...........but you already knew all of that...........
..........a bit more work than the basic bolt gun in general..................but to some........tis worth it............even in rimfire.