Thanks. That helps a bunch. It looks like the blue I saw in the engine compartment and trunk/interrior was a lot lighter, but the fender tag did say B7 :dontknow:
In either 71 or 72 the formula for B5 changed and the later years had a slightly darker B5 than the earlier years, although it was still a lighter shade than B7. Otherwise, as crackedback said, higher the number, darker the color.