Came across this 1965 Topps #173 Tigers team card with what appears to be a white back. It is not sun stained — it’s just missing the blue on the back altogether. Sun stained or exposed examples I'm aware of maintain the frame, but dull the blue to grey (or brown blue, etc.). This one's different.
Any ideas about this? Test issue? Promo? Just an error missing the blue ink on back? Information much appreciated! Thanks.
