It's the Circle M chip!

This chip, without inserts with a blue hotstamp is from Peru, IL

Other chips with the circle M were ordered by Herb Moran from New Britain, CT in 1946 but his chips were on the Harp mold

B Padgett from East St Louis ordered circle M chips on a T mold but didn't order any yellow chips

Tom Moore of San Antonio, TX ordered 606 Yellows on T mold but his chips all had inserts, the yellow having green.

The only one left was ordered by Frank Gregorich of Peru, IL in 1947. He ordered 600 yellow chips on a T mold with a blue hotstamp but his had no inserts which is the chip I listed.