<insert joke about Ric having me on ignore >
The time frame I'm thinking of for all of this is marbles from the 40's, packaged in the 50's. The patches in Post #3 are ones I would guess were from 1940's so it doesn't surprise me that they'd be in the stock Master bought from Akro.
I was surprised by the corks in Post #2. But in a way they made sense. I've never been sure of when cork production ended but the corks in Craig's boxes don't exactly fit the types I'm familiar with from the 1930's, so maybe they were produced later after all.
Chuck's aventurine marble looks more Master to me than Akro fwiw, but ......