The only thing that's not stock is that silly 9 pin Amphenol/WPI Series 86 "octal" plug on the back.
Can't find that plug ANYWHERE!
First, get the right Amphenol/WPI part number -- so that you can talk to "old school" parts distributors/dealers.
ALSO, be aware some suppliers categorize the part under tube scokets, rather than connectors.
Give a call to these suppliers:
Leeds Radio (NY), since 1923!http://www.leedsradio.com/parts-connectors.html
Amphenol 86-CP9, 9 pin, same pin circle as the octal.
This is used as the chassis mount power connector (male) on the Collins 51-S1 receiver. $9.00
Leeds also has the female (cable) side listed under tubes sockets. The female socket is Amphenol 78S9
Just across the northern Illinois border, along Lake Michigan is my favorite place for parts to restore the boatanchors:
Chester Electroncis Supply
7709 Sheridan Rd
Kenosha, WI 53143