That Snopes.com link doesn't really help your point, I checked it out. It mostly says that swag has never meant that. Additionally, the idea that it was used as some sort of code for gay guys in the sixties makes no sense whatsoever. Who uses "secretly" as the first word of a phrase? Why would they use a word that was almost never used until then? That just makes it stand out more. Is there any actual evidence (Urban Dictionary doesn't count) that it was used? Not just people saying that it's true, mind you, but like a specific example of it being used in the sixties?