No physiologist here, but I tend to think 'yes'.
The body, especially when young, tends to adapt to what it is repeatedly called to do, and configures itself to fulfill those requirements –– within the limits of genetic potential.
We are not at all astounded to see short parents who immigrated from a third-world country produce children much taller than them. The genetic potential was always there, but the nutrition was not. Kids eat well, grow taller than parents.
With musculature, we know that we are pretty much born with a given propensity to fast-twitch or slow twitch dominance, which we are not going to change very much.
We probably have a genetically (and hormonally) predetermined 'upper limit' on muscle cell replication/ production.
But you probably have accomplished giving yourself a higher percentile of 'potential' early on.