Those Warm Morning stoves also do a good job burning bituminous coal. US Patent Number 2,255,527 describes the firebox design of these stoves. It was modified a bit in later years, but the same principle applies. Since Lock Stove Works was in St. Louis, MO, they had to be able to burn that 'high quality' bituminous mined down in So. Illinois.
I personally like the cabinet versions with that classic two-tone brown cabinet. Very retro.