1770's-80's British Cavalry Sword for ID

[Will M]

This sword has not given up much in the way of what regiments used it or the Wyatt name on the blade. I have posted this years ago and thought there maybe information that has come to light since then so I'm giving it another shot!!
The sword is marked A/57 on the slotted guard, and on the scabbard locket. The blade still sharp is 36" long, curved and with a clip point. The name WYATT in capitals is stamped on the blade ricasso. One interesting detail is the buff leather strap on the scabbard having a slot in the strap for attachment. I have not found another example in my American sword ref books. I did see an identical sword in relic condition, without the Wyatt mark at Cribbs auction a few years ago, however was not able to add any info.
Having no access to American museums that hold swords limits my research.
The sword was sourced in Philadelphia. Was it a sword of the 16th or 17th Light Dragoons, or one of the many other Loyalist mounted units?
My intent is to tie it to a regiment and possibly find other examples.