But now I see that the concave blade doesn't match the concave bed on the plane. When the middle of the blade is flush with the bed, the side edges stick way out. The radii are slightly different between the blade and the bed.
This is my first concave spokeshave so I don't know if this is normal and I've been googling and so far no mention of anything like that so now I'm wondering if someone has replaced the concave blade so it would look complete. The odds that they'd find another Union blade with the same sort of mottling and wear as the other Union blade seem rather high, though. I suppose someone could have reground the blade long ago for some reason. Or maybe that's the way it was made.