Jillaine, you can get back clamping attachments online from several sources. If you watch shopgoodwill.com, they frequently have boxes of machine attachments that include back clamping. I have a 66-1 with back clamping, and I have found several feet that didn't come with the machine when I bought it.
Also, after cleaning the bright metal, put some car finish on them, and they won't re-rust.