Not a criticism but merely a thought for you to consider. And I admit I do not play either the 80s or the 70s because of the mystery card. So this does not matter to me but it might to you Bernie. But I could see where this extra information in the box score such as "bpHR 1-8" could be very revealing regarding which year card you have for a player.
So those playing the mystery card games may or may not want this particular enhancement. You might consider running a poll for those guys and try for a consensus so you do not get blindsided with complaints once those guys realize it.