I have what are probably the same shells. All brass, green tin, DU marked on the top wad, no paper inside the tin. Only marking on the tin is a sticker on the bottom that says "Made in Brazil." Since you are willing to shoot them, why not just cut out the wad on one and measure/weigh the shot charge? If you are using a modern shotgun, the powder charge should not be an issue. Easy for me to say, it's not my gun.
Or, you could send a sample out for pressure testing if you want to use them in a vintage gun.