Hi Guys, I just purchased a pair of NOS 6l6GCs that are supposedly Tung-Sol made. Looking at them they are black plates and look a lot like the RCAs. After spending a long time googling, it seems like Tung-sol made 5881s, which while similar would not be labeled at a 6l6gc so I am wondering, did I really purchase a pair of RCAs? Something else, or did TS actually make the GCs. If so does anyone have a thought on how they sound? Good news, if I don't like them I have a 30 day free return window. Attached is a picture for reference. I would have assumed they were 5881s if the 6L6GC was not screened onto the glass.