A little help from the printing experts, please...

[JollyElm]

I grabbed up this supposed (portion of a) 'printing plate' because I recognized it to be a 1962 green tint card. (On a side note, due to the almost complete coverage of the active area, I would assume if authentic, it was a black (K) plate. This is further reinforced by the player name and curl shadow, which are obviously 100% black, the only parts of the final card that are such.)



It was described as a metal plate, but I'm not 100% sure that's the case. The tactile feel, consistency and pliability would be described more like a strong plastic, almost a thinner version of a gift card, but my experience in the area is limited. While in no way definitive, my gut feeling says this is not a piece of metal. The possibility certainly exists that it is aluminum (doesn't stick to a magnet), but does anyone have any insight here? Could it feel like a thin, plastic gift card but be an actual 1962 metal printing plate? I've held/cut enough pieces of aluminum and tin to have an innate feel for metal, and this truly doesn't seem to fit that scenario. Am I just missing something?

I would appreciate any help I can get.