Coinsandcanada.com

I have several proof like sets from 1961-1967 and i have aquired 5 1967 prooflike sets that are in a cheaper clear plastic than all the rest. Has anyone come across this before?

For 1967 there were many aftermarket sets issued to celebrate
the Centennial. Some in cases, cardboard and plastic. I have
about six different variations myself including one made special
for the USA. It is probably one of those aftermarket sets.

This is the envelope and there is no COA with it

Those are aftermarket envelopes.
The RCM had plain envelopes and included a certificate.