I am also familiar with the 1993 CMA proof-like set, and have it in my collection. A 1990 CMA enveloped proof-like set is listed in "A Charlton Standard Catalogue, Canadian Collector Coins, Royal Canadian Mint Issues". CoinsandCanada.com lists the set as well, https://www.coinsandcanada.com/coin...1990&type=PL. I have never come across any dealer, auction, or other source that has posted a listing or image of such a 1990 set. Perhaps Charlton and C&C.com have it listed in error? I will try an email directly to the CNA.