That looks like the Monterey table, there is no cradle, the machine just drops in. Originally there would have been included a zig zag attachment. I have my mom’s short bed 301 with the same setup, she received it on Christmas, 1957. There should be a piece to drop in to fill the hole when you’re not using the machine. That table was the “Kids Table” in my youth for every holiday get together, and now it is my cutting table in my sewing room. That 301 makes the best buttonholes that I’ve ever seen. The machine is 61 years old, and still sees like a champ, I use it regularly.