Yankees 1969(?) Malanga set

[AustinMike]

There is a Yankees team set that is identified as a 1969 Malanga team set. I first saw it mentioned on Beckett's website several years ago. They describe it as "This 12-card set was issued in four strips of three cards each measuring approximately 8 1/2" by 3 3/4" and could be obtained from the artist. The fronts carry very crude black-and-white drawings of New York Yankee players by Rocco Malanga. The backs are blank. The cards are unnumbered and checklisted below in alphabetical order." The only other place I've ever seen it mentioned (besides Net54) is the book by William Wilen that came out in 2016, The Mickey Mantle Baseball Card Collector's Guide. He wrote that "This was a 12-card set produced by artist Rocco Malanga and was issued in four strips of three cards each. The cards contained black and white drawings of New York Yankee players." The first photo shows the set.

My first question is: does anyone have any information (advertisement, ordering form, etc.) that clearly shows the set was issued in 1969, i.e., is it possible the set was issued in 1968? I've looked online for a few months now and can find nothing. The reason I'm looking is because of a poster I picked up several months ago. It is shown in the second photo. It is 50 inches tall by 40 inches wide. I've included the 1968 Yankees Yearbook at the bottom to help with the scale of the poster and to illustrate why I have the question I do. The 1968 yearbook includes the poster. In fact, many of the player pages include the drawing of the player. I've included the Mantle page in the third photo. Besides looking online for ordering info, I've searched the four Yankee programs I have for 1968 and 1969 thinking they could be logical places to advertise the set and found nothing.

Second question: the poster was signed by G. W. Michas. Anybody have any idea who that is?

Thanks for reading and any info you may have.