Alpha Pokémon have the same base stats as the average Pokémon of the species. Alpha Pokemon are much larger, harder to catch, more aggressive, higher level compared to your team during the early events of the game, and have higher Effort Values than the average Pokemon. So no, a Level 25 Alpha Kleavor would not have a higher base stat value than any other Kleavor. You can see this for yourself by comparing the attack value of a level 70 Alpha Lucario with a Non-Attack boosting/lowering nature with a Level 70 normal Lucario with a Non-Attack boosting/lowering nature. After subtracting the amount of attack stat points gained due to EVs, their values will be the same.
