Following one of the Reboot Packs
showing up in London, I've got a bit of info on the specific gauge used on at least one of the Proton Pack props.
(Note: I hadn't realised the make of the boot, and by proxy the gauge had already been identified, some of the information on the image has already been posted in this topic.)
Much like the gauge on the Proton Pack at San Diego, the dial cover of the Olympia Pack was pretty weathered, but unlike it's American cousin the one in London had the majority of the weathering at the edge, and less towards the centre.
When looking at the actual prop I was able to read (as the photos also show) that the gauge reached about "50" at the mid point, and I could make out the "SH" of the Ashcroft logo with the naked eye - I wouldn't be able to read the "CROFT" until I got home and reviewed my digital photos.
Once I got the photos off my camera (and consulted photos taken by my fellow ghostheads at the event), I was able to determine that the gauge is rated from 0/100 PSI, and is from an arm of the company which is based in Brazil, rather than the United States. I did my best to clear up the label on the back (I wish I'd noticed it when I was at the display), but I wasn't able to completely clear up if the serial number was "T437", "1497", or some variation of the two.
I was also able to determine that unlike some of the 0/100 gauges, this one only appeared to have four increment notches between each of the numbers.
I was also able to rule out models that had different arrangements of the screws, the mounting point and of the location of "PSI". From this I was able to produce a digital recreation of the likely gauge (using some reference from existing Ashcroft gauges to fill the blanks) - my apologies for the omission of the PSI text:
Which likely looks like one of these in real life, minus the boot:
The closest matche I've found so far is:
ASHCROFT 20W1005PH 02L 100# 0/100 - 2" diam.
Comparing the markings on the Olympia Pack with the gauge on the Prototype Pack, it looks like the two feature different scales.