Hello Rory,
The number of the seal that fits without mutilating it is TC12234. It's rubber coated and the coating doesn't have to be removed to get it to fit. I've fitted 100s of these seals without any issues.
The machined bores in the aluminum housing that takes the bearings and seals, would have been machined on some type of milling machine, or special purpose machine, using individual boring bars, or a special tool carrying multiple cutting inserts to finish all bores in one application. Although cutting edges could be arranged on a gang insert tool to debur the sharp corners between faces and bores, clearly no thought was put into deburing the bores and hence, there are quite sharp corners on the bores of the Hub Carrier. With some machines of today, finishing all of the internal detail of the Hub Carrier, including small debur radii on all corners, could be done with the one boring bar, with the profile being Interpolation Turned as if with a lathe, but with a stationary workpiece as shown in the following video.
https://www.google.com/search?q=interpo ... V32QA,st:0
These sharp corners are not much of an issue when installing a metal housing seal and given that the original seal has a metal housing with no rubber coating, is the probable reason why not much effort was put into deburing these sharp corners. These sharp corners could make it difficult to fit even a perfectly sized rubber coated seal;accordingly, before attempting to install the seal, I break the sharp corner between face and bore with a hand deburing tool, which is a circa 5 second job.
Regards,
Bill