Craig - I have.
The weights of the object balls in my Super Aramith Pro set (new one year ago) are either 168 g. or 169 g. with the exception of the 1-ball, which weighs 170 g.
And I have done the bounce test on these as well...
and they bounce the same height as the following cue balls... my Aramith Red Logo (came with the set), my Red Circle (which weighs a gram less), and my Black Circle (which weighs 6 grams less than the set and is 0.020 smaller in diameter than my Red Logo)...
which tells me that all of these balls were made from the same formulation of phenolic resins.
The outlier is the Measles cue ball, which does not bounce any where near the same height as the rest of the balls that I have. It's a horse of a different color.