T. R. King originally sold 450 of your SMB chips in the Block font in four colors, including yellow, to Wally Betterncort, Pier 198, Wilmiington, California in 1963. Seems to be a gambling operation, as dice game equipment was also sold.

Later T. R. King sold 100 of just the yellow SMB chips to Steve Bryon, 114 E. First Street, Los Angeles, California in 1991. I guess they felt that after 25 years they could re-use the monogram in that font. They usually try to protect the chips from duplicates.

It may be impossible to tell which order your yellow chips came from. If you found that bunch of yellow chips alone, with out any of the other colors in sight, it might be more likely to be the second order. If you submit the chip to the ChipGuide I can more research on them.