I came across this discussion on spectrum.

https://robertsspaceindustries.com/spectrum/community/SC/forum/50259/thread/weapon-amp-armor-variant-stat-changes/

Scorched weapons/armor don't have any bonuses, but attachments do.

Looks like scorched attachments aren't properly affecting weapons in LIVE, but we should see this fixed in the PTU. I'll see if I can test it out sometime soon.