Yes, it was.
I assume that St. Joseph had fulfilled his purpose on earth and thus was not mentioned again. Those missing years aren't essential to Jesus' life story but there's nothing wrong with speculating.
“Those missing years aren’t essential to Jesus’ life story but there’s nothing wrong with speculating.”
I believe the Holy Spirit took control of Joseph and used him in the fulfillment of Divine Prophecy, assuring that Joseph was a Godly, compassionate man who taught Jesus what he needed to know in His earthly life among the common people.
I think those missing years were indeed essential, and Joseph’s role was significant; his workingman’s teachings prior to Jesus’ ministry, during the so-called lost years, though not overtly stated in the NT, shine through repeatedly in Jesus’ pastoral teachings, in His ability to speak of the Divine in simple words understandable to poor and simple people.
That Joseph considered “putting Mary away quietly” when she was discovered pregnant (as opposed to the custom of having her stoned to death) and then went on to marry her anyway (with assurances from an Angel in a dream) was huge. This decision not only protected Mary and her Child, assuring that “God among us” would be born of woman, but was further reflected in what Jesus did in John 8:1-11.
The possibility of repentance and forgiveness of sin —for all of us—was introduced into the world for the first time, and Joseph had played a role in that by first sparing Mary.