Reverse or Rebirth...?

Reverse (or rebirth) weapons are the same as Timeless weapons, except they're 2 base attack weaker, much easier to get, and has 4 levels, whereas Timeless weapons have 6 levels and are only able to be forged by killing Pink Been and collecting 3 Time Stones and other materials.

Also intresting to note, the "GMS" weapons in our data don't have the level icons according to the MTS (Timeless do):f6: