Hi Ed - while each Hi-Boy was special, this one is almost a carbon copy of the 1961 Hi-Boy pictured in Mr. McPherson's book with some rather slight differences. It's a bit frustrating that I can't just point to that photo for you - but if you have the book and can look there, you'll see the mounts and why I chased down a "scalloped" top mount. The seat is indeed down in the factory photo so you can see. I guess the ones that were in the car were slightly different at the bottom, and that's barely visible by magnifying close in the photo. Quite annoying to luck out finding the apparent "holy grail" of oxygen bases only to find there's another variety out there. The photo I posted at
http://www.professionalcarsociety.org/forums/showpost.php?p=841906447&postcount=70 showing the Oxequip variant is indeed smaller than this Puritan one. I've attached another photo so you can see the holes better (12 total) - this wasn't posted in the original thread on this car. If I can't find an original to measure/replicate/etc. I guess can use the holes present to draw up a template that in conjunction with the mount I have to CAD up one that's close.
This car does have a piped oxygen system with a mount for an M-cylinder (Maybe actually be a Q - haven't tried yet to see what fits) up front behind the soon-to-be-returning bucket seats. Unfortunately, this was partially disassembled and I am still trying to figure it out. Brass tubing goes under the floor into the two NCG 238-50 outlets on both wheelhouse areas. It's possible I'm missing the upper half that would go up into the cabinet. The hole with obvious missing large trim ring in the cabinet side is also found with a smaller missing trim ring on the opposite side of the partition. I don't have a good photo of that. It appears to mostly likely represent oxygen or the line to vacuum suction - but there is no good evidence either way except for the fact the hole is much larger than the still-present brass oxygen tubing below. The article from the Socorro Defensor Chieftain from 29 January 1972 claims after talking about the four-litter capability that "It is equipped with an oxygen duct system that will deliver oxygen to each of the four stations." This leads me to believe the two wheelhouse oxygen outlets were only the half of it - and the other two outlets were somehow in the cabinet area. There is a rhomboid missing item from the passenger-side wall of the cabinet, shown at
http://www.professionalcarsociety.org/forums/showpost.php?p=841906447&postcount=70 . My suspicion is this is either a mount for a Rico or oxygen outlet - indeed factory Hi-Boy photos from 1962 show oxygen outlets in that location. If a Rico - no Eureka factory photo shows one installed there, and it's never mentioned as an option. Quite possibly done long after factory if so. Either which way - can't find an NCG oxygen product or a Rico suction item that would fit the bill for the holes/profile.
Plenty of work remains to figure it all out! A photo from the 1980s of this car shows the hanging hardware missing/etc - so a lot of this stuff was probably pulled out in the late 1970s when it was sent from Socorro to Tres Piedras. The gentleman there I've talked to couldn't elaborate, but told me they pulled out a lot of stuff to "make it more functional." Honestly, I'm surprised with so many parts/pieces/tags that so much remained. Still hoping the hanging hardware turns up at least - he remembers it still be around "somewhere." I keep checking in monthly.
Kurt - no holes visible in the cabinet/partition outside of the big hole penetrating to the cab. Is that what you're referring to with 2-bottle bracket possibility?
On another positive note - after six months I found an elusive period-correct vacuum bottle (thermos) mount for the other side of the resuscitator cabinet on the passenger side. I'll never quite understand why folks thought a Thermos was a critical item of ambulance equipment - but no matter. The originals in the factory photo of the Hi-Boy from 1962 in Mr. McPherson's book appeared to perhaps have a fire-extinguisher hold down versus this spring - but this will at least allow for a template of some kind if not right.