Guild Wars 2

Them small treasure chests doted about the map more so the 5/6 of them inc the JP chest in cursed shore can they drop a precurser? or is it just from dragon chests.

Yes they can drop from everything, so not only those chest but also mobs.

The rarity is however extremely high, so it is prolly easier to win the national lottery.
I suspect the change to get the precursor as a drop is bout as low as getting it out of the mystic forge (without buying any of the rares/exotics or crafting them).
However these chests also drops rares/exotics that can be put into the forge, so go ahead and try .