What is the "means of production" other than those means by which goods are produced? Can any goods be produced without any labor inputs? Even a machine which automates some of the production processes, requires labor inputs to produce the machine, to maintain and repair the machine, as well as labor inputs to feed the machine raw-materials (those materials themselves requiring labor-inputs).
I therefore conclude that labor is a necessary condition for production to take place; which is to say, without labor, no production is possible.
If no production is possible without labor, then labor is the primary means of production; it is the mode by which production is possible.
For labor to take place, a mind or consciousness must direct the body to act in meaningful and purposeful ways; therefore without mind/consciousness, no labor is possible and therefore the mind/consciousness is likewise, the means of labor.
The mind directs labor in purposeful action, in order to satisfy human-needs, either for one's self or for the needs of others in gift or exchange for the products of labor of others.
Therefore, each individual, possessing a mind and a body by implication of their mind directing their action in labor to satisfy needs, possesses in themselves the [primary] means of production. Through these means, they may fashion labor-saving devices in order to increase either their production or their recreation; these additional but secondary or tertiary means of production may become increasingly complex but they all fundamentally proceed from the individual's control or possession of their own body by their consciousness.
Therefore, all persons by their minds' control of their bodies, possessed to the exclusion of others, the means of production.