I'd go for the gun first.

Then you go for the lance if:
1. You have the extra ori for it
2. You project your fire grid to not have 10 dual skill SSRs by April (if you need 4 copies) (also, wind tower quest should be at the end of April)
Alternatively, you project your fire grid to not have 10 dual skill SSRs through the end of the year, either because of not having stars to FLB the weapons from Wrath or some future events just offer not-completely-desired stuff (single skill assaults, or dual skills without either assault/pride)