Ah What Da,
of course this is Ridiculous.
As noted, there is overwhelming physical evidence for the existance of nuclear weapons
Only a complete idiot would serious consider, much less believe otherwise.
As propaganda;
It's much more plausible that the actual numbers of these weapons and/or their yields might be inflated.
In theory; those sub-terranean based delivery system emplacements located in several US mid-west States could consist of a certain percentage of "Prop" Missiles and/ or payloads.
Unless someone has Top-Secret clearence, knows the Science and personally lay eyes and hands to each and every of these for inspection; how do the rest of us know that some of 'em aint foam,fg and paint???
Theres a Do-able conspiracy for you, the BS missile program......