NOS Direct Connection Blue Small Block Valve Covers

Those ARE sweet! I'm glad you've got others interested because I don't think I'd dare bring in another set of valve covers.
For different looks I've already got my polished 'Mopar Magnum' cast aluminum covers, my "old school" Cal Custom finned polished cast aluminum covers, and a brand new set of gold-anodized aluminum Moroso covers.
But your blue-anodized ones sure look good!
Good luck with your sale.