I was lucky to get a soft ivory 500, but I thought this would be a good pickup for someone here, then I noticed the back of the phone--ouch!
http://tinyurl.com/p9br3y ( dead link 02-28-22 )
I noticed that one, too. I thought it was odd that the back was modularized, but not the handset. I wonder how that would happen.
I have a 59 Moss Green that was cut in the back and a modular plug was added. It didn't look like a Ma Bell job, because the slots were rough . I only bought it because it was so cheap, and it was my first soft-centered fingerwheel phone.