Here is Bulbapedia's bit on the Gens 1 & 2 equivalent of EVs, "stat experience". I will draw your attention to choice bits with

**blue bold text**, but really the entire excerpt is worth reading:

In Generations I and II, effort points given are equal to the base stats of the defeated Pokémon species.

The Pokémon data structure contains two EV bytes for each of the five stats (HP, Attack, Defense, Speed and Special), starting at zero when caught and with a maximum EV of 65535 for each stat. When a Pokémon is defeated, its base stats are converted to effort points and then added to the EVs. For example, **defeating a Mew grants 100 effort points to each EV. (Defeating 656 Mew, therefore, will give a Pokémon maximum EVs in each stat.)**

EVs are factored into the Pokémon's stats when it levels up. Additionally, EVs are calculated into stats when a Pokémon is taken from Bill's PC; this is called the box trick. A Pokémon which reaches level 100 can continue to acquire EVs up to the maximum of 65535 in each stat, and use the box trick to have those EVs factored in.

Vitamins add 2560 to one stat's EV, but cannot raise a stat above 25600.

At level 100, the formula for determining the stat difference between a Pokémon trained in that stat and an untrained Pokémon is sqrt(Stat Exp) / 4, with the square root rounding upwards unless that would take it above 255, and the whole calculation rounding downwards.

**EVs behave the same in Generation II as they did in Generation I.** Both Special Attack and Special Defense share the EV for Special to maintain compatibility. The amount of Special EVs received is equal to the defeated Pokémon's Special Attack base stat. The box trick can still be used.

So basically, the higher the base stats of the Pokémon you KO, the higher the amount of Stat Exp you gain in any particular stat. KO an Electrode (base Speed of 140) and you gained 140 Speed Exp points. KO a Machamp (base Attack of 130) and you gained 130 Attack Exp points.

Also, the more Pokémon you KO'd, the likelier you were to max out any given stat's experience. Like the article says, if you were to KO 656 Mew (who has a base stat value of 100 for every single stat in the game), then you would max out all of your stat experience points -- because 65,535 is the maximum number of experience points you can have for any given stat and of course 656 x 100 = 65,600 > 65,535.

You might recall from childhood that players who doped their Pokémon up to Lv.100 on a diet of pure Rare Candies generally had weaker Lv.100s than did their hardercore companions who raised their Pokémon the old fashioned way. This is why. Rare candies don't give you any Stat Experience, so the only stat gains you were getting were the ones built in to up-leveling.

You might also recall from childhood that early "EV" training spots included Silph Tower (for Special), Rock Tunnel (for Defense), and Diglett Cave (for Speed).

If you've already accounted for all of this ... then it's probably just due to genetic variance. Kinda hard to believe that your GSC Nidoking would be inferior in all five/six stats (which is why I've included all this text above -- because I'm sort of convinced it's the EVs you're missing, not the IVs), but it

*is* technically possible. After all, it's only a (1/2)^6 chance that all six of your GSC stats would be the genetically inferior ones. That's only a 1/64 chance. Not that small at all, really. Not in the grand scheme of things.