While making the howitzer inoperable, it wouldn't solve the problem of drawing fire. The enemy wouldn't know whether the howitzer was in working condition or not. They would still have the problem of getting rid of it.
"B. O. Plenty" was a character from the Dick Tracy comic strip.
When Kwang is leaving the 4077th and Charles refuses to shake his hand, Charles laments to himself, "He [Kwang] was like my own boy." However, Sab Shimono, the actor who portrays Kwang, is more than five years older than David Ogden Stiers.
After Potter orders Hawkeye to get rid of the cannon, Hawkeye can't find any takers, and won't send it to an active battle unit. He could've simply contacted Sgt. Chimoli and ordered him to come retrieve it and put it back in the supply warehouse, where it came from.
Upon embalming the howitzer, Haweye quips, "death takes a holiday". This will be the title of Season 9 Episode 5.