Be aware there has been more than one version, and depending on which model Shopsmith you have, one may be better for you than another.
Here is a link to a thread about the different versions.
https://www.shopsmith.com/ss_forum/woodworking-tool-review-f9/tool-shelf-t378-s20.html
Also, attached is an installation instruction sheet from 2004 which shows the then current model with accessories installed from three different models.
Shopsmith Accessory Storage Shelf 555953.pdf
