I know I have seen at least two references to the burning of Dallas but all I can lay my hands on is in Silvana Siddali's excellent book "Missouri's War" where the following appears:
"Saturday Nov 15/62... Passed though Dallas now deserted by all of its inhabitants except two or three women. The houses are all more or less destroyed, some being burnt to the ground. This place was a regular den of secessioners and last spring Hecker cleaned out the crew and destroyed their property."

This from the diary of one David Allan, Co. D 29th MO Volunteers.