There is an obscure story, whose origins have been lost in antiquity, that could support your assertion above. I offer it for what it is worth.
The way the story is told, a dispatch rider traveled 80 miles to deliver a copy of Lord Dunmore’s Proclamation to Thomas Jefferson.
Before Jefferson could read the document, the rider blurted out: “Lord Dunmore has called for slaves to start domestic Insurrections and to fight their masters!”
Jefferson was ashen faced as he mumbled to those assembled: “This is terrible news. Domestic slave insurrections would be bad for me as a master, bad for New York and Massachusetts and other slave states, and bad for the proposed revolution.”
Then, the story goes, Jefferson read Lord Dunmore’s Proclamation in its entirety and began to laugh out loud!
“This is great news,” Jefferson exclaimed!
“Lord Dunmore has not called for slaves to participate in domestic Insurrections and fight their masters. Lord Dunmore has only called for slaves to rise in arms and fight their masters,” Jefferson continued.
“This makes all the difference in the world,” Jefferson was reported to have said.
This story could be the missing link that proves your point. If I were you, I would embrace it.
Pure fantasy, worth nothing.
Dunmore offered freedom to slaves who joined the British army, period.