Thank you for the input!
I initially had the Yor-Lok fittings in my Shoebox spreadsheet as I had found them as you stated, on the McMaster-Carr site. (Much of the parts for the Boxes are from McMaster-Carr, so it makes sense from a purchasing point, I suppose.)
However, they are not the same fittings as the OP, which seem to be a swaged fitting, likely using a hydraulic swaging tool (?).
There were a few iterations of fittings on the Shoeboxes as they went through the 'Betas' to the F-8/10 models. The F-8 is the one that I have and include the OP fittings.
Yes, the Box will easily go to 4,500PSI, that the auto-shut-off rate too.
I'll head back to McMaster-Carr and check the Yor-Loks out more closely.
Sounds like your experience is hugely valuable in locating this sort of fitting (that's why I'm asking on AGN, HUGE knowledge base). While I have used many fittings in my career, (Swagelok in particular) I never ran across the swaged 'Barrel-Style' fittings per the OP.
Mike