Side note, but to back up the fact that EVs were around, yes, EVs existed in Gen I, but back then, they were called Stat Exp. Proof of this lies in the existence of the Box Trick, where after battling a bunch of a single species of Pokemon (Pikachu for example), you deposit your Pokemon into Bill's PC and immediately withdraw it again to have stats recalculated according to how much Stat Exp the Pokemon you've battled gave out. (You can actually still do this, as stats, if I recall correctly, are still recalculated every time you withdraw Pokemon as well as every time you level up.)
You can find out more about how the trick works
here, which probably goes into better detail about it than I could. ^_^;
If I recall correctly, though, there were less restrictions on how much Stat Exp a Pokemon could learn (Don't quote me on this part.), although the very most you could boost your Pokemon's stats might've been the individual species' maximum possible stats. Four Stat Exp points still went to one stat point either way. Additionally, stat boosters worked the same way they do now by adding Stat Exp to a Pokemon's stats, according to the stat booster it consumed.
And yes, DVs (now called IVs) existed too.