I asked around about this for you, as I am also interested in maybe buying some for a stove I have, if anything just to see how it works.
Of course use at your own risk, I/we cannot be held responsible for what your ultimate decision and actions are.
I'm not offering a definitive guide, or promise, as I am not an expert and the advice I got from the experts came with limited knowledge of what you have, and then only based on the description you offered.
The answers and advice I received from the local heating experts in my area summarized.
What you have *sounds* like the genuine article from your description.
Most older coal stoves were a heavy cast iron, or thick plate metal (but then normally includes fire bricks).
They are built to handle the "normal" operating burning temperatures of coal, but NOT the maximum temps that can be achieved with a forced air induction, or a runaway stove that cannot shut its airflow down to a safe level.
Things to be careful of are:
The first and what everyone stressed to be the most important:
An older stove MUST be capable of shutting down most if not all drafts in case of a runaway.
A stove that cannot is a hazard.
You would be running a risk using it with any type of coal
Flu and piping must meet higher standards of how good is good enough.
As one would presume with the consistently higher temperatures of the coal.
Coal has a very long heat up time, and similarly a LONG cool down time, plan accordingly.
Never try to dowse a coal fire in a cast iron stove, as the stove may break or shatter from the temperature extremes, the hot coal then also may be released causing injury or fire.
Be careful using coal in a stove that has burned a lot of wood, check the chimney for soot buildup.
The coal may ignite soot built up from wood.
Like I said, I cant be held responsible, but these are what I was told were important to consider when burning coal.