I'm the one who had the Spica paint custom-mixed by Tower Paint in 2002.
From the label on my can:
ALFA ROMEO GRAY
FOR AIR CLEANER
I can't tell you the current cost, and hopefully, they've retained the formula, but I can say the color/tint was perfect, as was the not-too-glossy sheen. For the best results, have your parts bead-blasted first and use a quality primer. Other paints I've seen have far too much blue tint in the gray and and far too thick and glossy.
Nice job on the plates, and if I still had my '74 Spider I'd have purchased one. Someone was making the FISPA stickers a while back, but I can't recall who it was.
Dean - '87 & '92 Spider Veloce's