Firebrick it for wood. Coal is extremely hard on metal chimneys and pipe, plan on replacing the cap every other year depending on coal used. If you are using coal, consider a masonry chimney. It also drives up the price of installation with a barometric damper.
Coal stoves require replacement of grates and liners periodically. When Fisher went out of business, very few replacement parts for the coal basket and grates existed. Most have homemade grates and liners and only the stoves that have burned only wood have grates in good shape. By 2000, most customers needed the parts that come into contact with coal or fly ash and most were scrapped when parts couldn't be found. That's what makes them rare today. Most were installed in basements so nickel or brass is more rare than black. Very few were plated.
Pros and cons of coal burning; Anthracite coal is a very consistent burning fuel without the temperature spikes of wood. Once lit, shaken a few times daily and stoked, they burn constant until left to go out in the spring. In a garage or shed you may want to only fire it when you're going to be there. It takes a few minutes to establish a coal fire, but hours to start radiating constant heat. Not the fuel for quick heat like wood.
As stated above, fly ash is very corrosive to metal and even masonry. The ash is alkaline, so it can be used to correct ph of acidic soil. It is great for soil conditioning, but has no fertilizing value. It is primarily a coal burner which takes wood cut shorter than a Bear Series stove.
The Coal Bear is a stoked stove, meaning you shovel or pour coal on the fire compared to a hopper stove that feeds itself by gravity as it burns down or you shake it. Advancements in coal burners now include thermostats and hoppers to self feed. Most have glass doors to see the fire so you know when you have a blue secondary flame (very important to keep coal gas ignited and not build up until you open the door and oxygen ignites the gas with a violent poof) They are best for people with at least some coal experience since seeing the coal fire with door shut is different than when door is cracked open to peek in. There are many tips to filling properly by keeping a shallow hole in the fire to maintain a pilot light of sorts, to firing with different size coal (the fines in the bin) for when a slower burning fire with less heat is needed. Preferably a horseshoe shape fire, with less in the center, or mounded, not flat or level ! Control is difficult without glass and you only learn with practice.
I was contemplating making patterns for liners and grates years ago, but never had much of a need for them. It's something I could produce and have a few sets for years without moving them. Just not profitable.
No manuals have surfaced, but coal burning is pretty standard with any coal burner, so I can walk you though that if needed.
