Shot type is not a good header--Clays, along with a size id would be much better.
Any lead or steel type shot would be able to be recognized by the weight of the marble/orb in hand.
These are simple clays that are very hard to ID as far as the maker or where they came from.
I like them and over the years I have found these in "Lot's" of marbles".
Nothing goes to waist in my house--my wife loves them as do many folks for a "Decorator item"--many kept in a small glass jar mixed with some other does make a great display.
Marble--On!!