When RS exports undistorted images, it does not seem to record the focal length anywhere – not in the EXIF, nor in any information file that I have found. The focal length in pixels is of course fundamental to relating any image to 3D geometry.
I would assume that the undistorted images simulate the nominal focal length and pixel pitch of the corresponding source image. However this should be made explicit.
If you could provided full pose and projection parameters for exported images, this would enable exporting other geometrically corrected views as well.