Before Fair Radio went out of business, I had the opportunity to pick through it a bit. Much of the WWII stuff was gone, but they did have a few PRC-6s.
I was able to find enough parts to complete the unit, including the mic and antenna.
The one thing it was missing was this JHY 3B4 tube. I found one on ebay for 9 dollars in Jan 2024. Below is what the box looked like. It was 4.5in long (from one end of the box wings to the other) and 2in high. You can download a pdf of the box if needed.
It was also missing the primary crystal, CR-23/U Quartz Radio Crystal HC-6/U, and the spare. I bought two for 32 dollars in Jan 2024. It did not come with box.