I unwrapped it carefully and examined it for a long time before trying it out.
The pad is about the same size as many factory-made, mass-produced pads of the era.
It has thin-walled wooden sides and a curved plexiglass top mounted on a wooden base.
The pad mounted on the plexiglass is made of rubber that is quite cracked with age.
There's a steel rod running through the middle of the pad, that can be tightened or loosened to change the pitch of the pad. The notes from my research say it was originally able to change by as much as two whole tones. I won't attempt such a stretch now because of the pad's age (and the wooden sidewalls seem pretty thin).
The sidewalls, slightly warped from use and time, do not reach the platform. There's a tiny open space at the bottom of the sidewalls to allow for the adjustment.
I will have to guess at what other pitches might be possible. I don't mind at all.The pad is in amazing shape considering its age.
There appears to be an imprint from a decal or badge. I thought they might be lettering from a logo, but it could just as easily be squiggles of thinkly-applied glue. I just don't know.
The rubber circle, not quite 4 inches in diameter, shows a lot of cracking -- but it's also still very pliable. I played with sticks and was surprised at its bounce and response. In fact, I decided to make a little video so you can all see how lively the thing is, over fifty years after its creation.
This is one of the coolest finds ever in my quest to research and learn more about practice pad design and development. I'll keep looking to see if I can find a patent (which would be cool, since it would fill in some blanks historically and mechanically).