The blue one seems older and different than the others. I don't see a pontil on that one. It looks like it has blue and white striping glass in a clear base - am I seeing it right, or is the base glass blue?
I appreciate the extra pics because they are intriguing marbles. I'm thinking they're newer, maybe Bulgarian, but I can't say for sure - they just seem off for early American marbles, at least to me.