Weight Question?

Yes, of course there are authentic coins struck in the appropriate metal that are well out-of-tolerance weight wise. It's not at all common so errors such as this usually have significant value once authenticated as genuine. And by all means, purchase an expensive gram scale. For $15 you can get a good reliable scale that is accurate to 0.01g.

I have a few scales and USED to use them for coins. Then I constantly thought all my scales were nutty. So many times I'd get odd results on similar coins. Then I had to remember that as a coin wears, it looses weight. Ahd if it's dirty, it gets an added weight. Also, I'm sure that the tolerances in weights right from the Mint is something that is not publized much.
As to your 82 Cents, rather than a scale, just use a balanced beam system. Balance a popsicle stick on a pencil. Place one of your 82 cents on the far end of the stick and a new cent on the other end. If it balances, your 82 is a Zinc one. If Copper, that one will fall down.

More or less than what? Spec weight? If that is what you mean then yes there are. There are also error coins that are struck on planchets punched from strip that was either rolled to thin or thick and the resulting coins that have weighs outside of the mint tolerances. These can vary from slightly out of tolerance to way out. The further they are from tolerance the more valuable they are. One warning though, counterfeit coins are FREQUENTLY outside of the mint tolerance so any coin with a weight out of tolerence should be looked at with skepticism.