Riven mods reroll

[GODyr]

Hi warframe community! Have some question about rerolling riven mods. When use reroll u reroll only option ore weapon? I got mod for supra from the war within quests, after 2 relolls I got rivens mod only for supra. If u look count amount rifle in warframe it is rly low % to get mod for same weapon 3 times in row. Also what is % on spawning harvester? Have seen in found and videos that it is ~30% mby I am just unlucky whit RNG but from 60 runs I got 3 spawns and 1 was bugd so harvester will not stat to harvest. And mby some one know % on geting riven mod from Sortie daily missions?

[Dromeos-Prime]

You only reroll the stats of the mod not the weapon.

Harvesters are rare in general though.