Honestly I really have no idea about the tights. In those day everything got embroidered, so I’d guess it wasn’t terribly unusual. Someone better to ask would be a reenactor.
The American Revolution itself was launched with the signing of The
Declaration of Independance. The signers of The Declaration actually
sat around for hours debating whether or not to actually sign the thing
because signing it meant they could all be executed for treason. The
Continental Army was formed as a ragtag, ill-equipped militia and had no
official uniform. Britain was caught up in larger military
involvements with France, and King George III suffered from recurrent
bouts of mental illness. Naturally, France leant its force to the
Continental Army, and it largely due to this that The American
Revolution was won.