jake the snake

Frosty, how old might this tool be? Is it worth anything? It actually doesn't look very old, rusty yes but not old.

New to the site. My grandfather also gave me something similar. He always called it a sheet metal workers anvil but I tried to find it on the internet and have no luck. It's not nearly as heavy duty as yours. But does have half round extensions, though. One of the photos is shown with it upside down. You can see where it is meant to bolt to a table and slid back-and-forth as needed. You're help would greatly be appreciated on its identification.