(a) An employee commissioned by the director as a peace officer may purchase for an amount set by the department, not to exceed fair market value, a firearm issued to the person by the department if:
(1) the firearm is not listed as a prohibited weapon under Section 46.05, Penal Code; and
(2) the firearm is retired by the department for replacement purposes.
(b) The commission may adopt rules for the sale of a retired firearm under this section to a peace officer commissioned by the director.