Factual error: When BJ and Hawkeye go to Potter to talk about Cho Lin wanting to get married at the 4077th, Potter mentions he expects to be home in Nebraska in 16 months, three weeks and four days when they try to fool Potter about Cho Lin. Potter has always said he and his family live in Missouri, however.
Factual error: Unless the regulations for the time period were different, the belt buckles seen with the regular fatigues is incorrect. They should be the same color as the belt and/or uniform. The brass buckles seen were used with the dress uniforms only. Also, any rank insignia worn by officers would have been dull in color so that they would be less of a target to snipers.