Plutonium is very corrosive and sensitive to phase changes so it needs to be refurbished and replaced regularly. The weapons grade plutonium lying around is probably not bomb ready.
Without casting the military as lying, if they declare they have <x> weapons in substantive state to be used, and place them in missiles, then the implication is they maintain a stockpile of pits capable of meeting that supply, constantly.
If we assume 1 pit per month ages out due to phase and corrosion, then they would presumably have a pipeline of 12 pits in refurbishment continuously.
Since the stockpile is still measured in the thousands, I would assume the stockpile of plutonium pits running through pantex facilities is at a similar scale.
(this also assumes there is no neutral gas non-corrosive, phase stable storage)
If we assume 1 pit per month ages out due to phase and corrosion, then they would presumably have a pipeline of 12 pits in refurbishment continuously.
Since the stockpile is still measured in the thousands, I would assume the stockpile of plutonium pits running through pantex facilities is at a similar scale.
(this also assumes there is no neutral gas non-corrosive, phase stable storage)