I have 4 or 5 of these, all some of the more common varieties., all purchased in the past 2 years from matthijas, a prolific dealer from Belgium on
ebay.
I suspect that even the "common" ones are undervalued in Scott because I just don't see them very often for sale.
That you have a MNH block of 4 should make your stamps considerably more valuable than the CV for 4 singles.
Thanks for showing them here. They were fun to see.