Couple of problems with this idea. Firstly, a bad paint/bore match can make up to 40 fps difference. And it's not just manufacturers that store the paint, there's the shops/sites that sell it, & some players keep theirs at home for a while. Then, as Pete M says, there's humidity to take into account.
Secondly, the temperature can make a difference even with air to a small degree, & with CO2 it can make a big difference.