Yeah. Only thing I would allow for a Mando is their more underpowered armour. If you wanna look like Boba Fett, go ahead. But your armour isn't totally resistant.
But you raise a good point. I'd forgotten about those. Well... I'd say because the Jedi are basically eradicated from the galaxy and only two Sith remain, nobody would really possess those metals/materials because either:
• Palpatine destroyed any and all factories producing the items containing the metals, as well a sending out clones to confiscate the items that had been previously sold
• Nobody wants to have these weapons because they fear Palpatine will see them as a threat and force their immediate excecution.