There are some other differences.
Generally speaking, the stainless Blackhawks came with a brushed finish, while the stainless Vaqueros (and New Vaqueros) were polished.
Up until a few years ago, blued Vaqueros had a simulated case haredened finish on the cylinder frames; Blackhawks are entirely blued. (Vaqueros are now entirely blued, too.)
Blued Blackhawks generally had aluminum alloy grip frames (with some exceptions), while Vaqueros had steel grip frames.
With the exception of some special, relatively low production models, Vaqueros have been offered in three barrel lengths: 4 5/8, 5 1/2, and 7 1/2. The Blackhawk models had a larger variation over the years (the sizes listed above plus 6 1/2, 10, and I don't know what else.)
The cowboy style sights vs. adjustable, target style sights are the biggest difference.