Added location.
Have no idea how to turn the pics or why they posted at a 90 degree rotation to start with. Not that tech savvy.
The older gentleman I got them from said the plates were bandsaw anvils that he worked large bandsaw blades on for what it's worth.
Yes the round one is slightly conical with grips cast into the side. It appears to be solid steel and does not have a hardened face plate like my Fisher. I would guess the top,face at roughly 10 inch diameter an the bottom at 12. I'm at work now so I can't get the exact measurements.
Will try to post a pic of the grips. Maybe it won't rotate on me.
Not the best pic, but you can see the grip on right side. There's another on the opposite side.