The official designation is "H8". To further fine tune your research, you have an Early H8 that has the earlier claw mechanism and the sprocket teeth are a little more rounded in their design. Also, your 100ft load spindles are completely round rather than the more normal round with a square at the base. You can take the serial number as shown in your pictures and get a full breakdown of your camera and it's relative specs at http://www.bolexcollector.com
A couple of things to note. The early round spindles use a different daylight real than more modern versions and can be difficult to source at times. And, your lenses are some of the better lenses that were available for those cameras so unless you are trading up, hold on to the because as I've said, $20 was a bargain. The first photo of the two chrome lenses are going for about $100 each on eBay these days with adapters that allow their use on modern digital camera with astounding image results.
The reg 8mm film is still available today and processing as well, just not as common as Super 8mm and up.
Here is one, http://www.cinelab.com
But yes, it was a very common method which pre-dated the Super 8mm cartridge format of film making. Reg 8, and Double Run 8, and Double 8, are all used for the same 8mm film and it's processes. But that is why they call the spools you load the film onto "Daylight reels" because once you've exposed the first half, the you turn it over in full daylight, although, I would recommend a darker area, and the black sides of the reel protect all but about the first three outer layers of the exposed film. Which you would be damaging during the rethreaded process anyway.
I actually to and H8 "S" and mounted a Bolex 400ft external Magazine so when I shoot with it, I get roughly the same amount of footage as someone with 1000ft of 16mm.
It is still a viable format for the average filmmaker and there are whole clubs and websites devoted to the format, there are also so mods that can be done like Double Super 8mm that widens the gate to super8 aspect, and still uses the double run method of capture, also, one of my dear Friends whose birthday just happens to be today, worked out a system called "UltraPan 8" and has an aspect ration wider than Panavision. He is a member here as well, His name is Nick Kovats.
Let me know if there is anything else I can do. Always good to see a new Bolex user.
I have shot ARRI, Anton, Eclair, and Bolex to name a few. And, my favorite will always be the Bolex.
I shoot film exclusively and with the Bolex cameras, if some happens on set or on a shoot, I can completely tear one down and rebuild it on location and be back up and running in no time.
That is a fine piece you have there so make sure you know what you have if you ever trade or sell it.