If you run out of weapons to run for IW, consider the suggestion in the title.

Since the IW stats stay with the weapons after upgrading, it is a good time to buy both base forms of these two weapons (50 dark matters each) to make the best out of the double boosted rates in this compensated IW period.

Cheers

Note 1: These two weapons could be obtained from Mog Captain Guard (the one standing on the right in Mog King chamber) for 50 Dark Matters each.

Note 2: Dark matters can be obtained by participating in monthly Dark Vision event.

Note 3: All weapons that are upgraded in the "Enhance Equip." tab can have their IW stats carried over through their upgrades with no issues. I personally tested this on Dark Ragnarok and Esper weapons. Gumi made in-game announcement about this a while ago.