Unlike metallic mechs, biomechs could never achieve perfect or near-perfect consistency among copies.
Biomechs were grown, not built, so variations tended to occur much more frequently.
However, once biomechs had completed their relatively rapid growth process, their organic forms largely became fixed.
Even if they incurred large amounts of damage and subsequently regenerated back to 'full health', biomechs always tended to return to their initial mature templates as best as possible.
Perhaps older biomechs may still show changes and evolutions over time due to the natural aging of their organic components, deviations from feedstock or receiving particularly serious damage.
In most cases, the biomech pilots and the people that maintained the organic machines tended to view such changes as undesirable.
