The next type was the red and white hinged RST4 box like this one. They put stickers on the end for anything else that might fit in there. The other box was for a 6.5" Blackhawk marked BN36.Those were used from the early days of the 6" Standard,, until sometime in the 1960's. I'd have to go back & study a bit to narrow down the next type of box used, and when it became standard. But I believe it was well before 1973.