Back in the 30's when this box was put together no one was too worried about what went into a stock box. There were buckets, barrels and tubs filled with marbles all over the production floor.
Anyone who has spent time in a factory where production was stressed ( and especially in the 30's when marbles were cheap and so was labor ) would know that most "stock" boxes were probably filled with whatever marbles that they had the most of and wanted to ship. With the possible exception of "gift" boxes which had somewhat various matched color marbles, the goal was to make and ship as many boxes of marbles a day that you could. No one picked them up and looked at them to make sure they matched.
Since a 50 gallon barrel might contain the same color and type of marbles from a few different days runs, it's not surprising that Lee's box has slightly different hues and bases.
And that's not my humble opinion , it's my opinion from spending more than 30 years in a variety of manurfacturing plants from the 50's onward watching piecework and production lines. None of that IMHO cop out....... Art