Remembering that Crazy Horse led a fight at Redbud Creek that resulted in an Indian victory shortly before Little Bighorn.
Among that small band were about 30-35 members of the Dog Society (think Marine Recon or SEAL lifers) armed with Henry rifles. Futher at least three members of that band had served with the South during the Civil War. Indian naratives atribute plan and execution of the initial ambush of Custer to this small number of Cheyenne warriors.
Its not only likely but even certain that or something like that happened to not only change the usual way Plains Indians fought but to do so effectively. After the serious losses in the opening seconds of the battle the Indians piled onto the the doomed 7th.
Your memory is a little faulty in this case, as the battle you refer to was the “Rosebud”, not redbud. Additionally, it was more of a draw then a clear defeat.