I've had several of the El Monte Club chips since 1997 as Eureka. I got them from Joe Bennon and Mel Jung.
After your post, I had the records from Portland Card Company pulled.

They are Eureka.
Several orders in 1961 of both DiSq and SqinCir chips.
300 of your Lavender 10¢ was delivered on 3-21-61.