The story of the 150 "boys" must come from someone counting up the number of names on the company roster. During the ENTIRE war about 152 men served in the company -- this includes recruits, conscripts, transfers and the men assigned from the disbanded 2nd Arkansas Battalion. If I recall correctly, the Tulip Rifles as originally organized mustered about 90 men.
I have been researching the 3rd Arkansas Infantry for over 30 years, and I've read everything I can lay my hands on, including numerous letters, diaries and postwar reminiscences -- no one, at no time, mentioned anything about dragging cannons along with them. The records of the 3rd Arkansas include periodic arms and ordnance reports -- all that's ever mentioned is small arms; nary a cannon to be seen.
The newspaper article is pure bunk, and I'm very disappointed that the esteemed institution you mentioned would accept the article as written and teach it as fact. They are doing a great disservice to the people and schoolchildren of Arkansas.