Really? Why’s that?? He was already a General prior to the conflict, and in the story cited, they did say he had his ceremonial general’s sword with him when he was KIA.
1st of all, it wasn’t established what uniforms would be, even for officers.
2nd, rebels were never in a position to reliably clothe soldiers the entire war (especially in standard uniforms), much less any person at the literal start of the war, which for all they knew would’ve been quelled in a couple months anyway. They were not prepared militarily in any way - not even uniforms. Most “officers” at Boston were even in regular dress.
3rd, many, many images of the RevWar are romanticized, and many are well after the conflict. E.g., common belief is that rebels of the RevWar wore red-faced blue, whereas in truth many were hardly clothed at all, many wore homespun “hunting shirts, and that the red-faced blue uniform was a much LATER standard for mid-Atlantic troops. That (limited) standard was based on MD and DE troops, who, incidentally, were the BEST in the war - MDers were legendary - and they frequently wore these colors. Hence, it may be that people wanted all their RevWar heroes to all be dressed well & colored as the heroic troops were, not to mention their similarity to the flag.
“Ceremonial sword” may have simply been something he possessed ancestrally, or from an earlier conflict such as F&I.