No damage is not a flat value. It takes the attack value, impact, range and other values, and adjusts it according to your level and your targets level. The damage you do is greater to lower level targets and less to higher level targets. Those shooting at you have the same thing done with their damage output. Critical hits are a flat adjustment to this by weapon type, for example auto rifle crits are always 2.5X the non-crit damage.
This damage adjustment is what they are referring to when they state level advantages disabled in PvP. Equipment is not adjusted for in PvP.
So searching for the displayed damage will only result in the answer to the equation and not be useful. You would be better off searching for the weapon blobs and reversing them so you can adjust the damage multipliers rather than the resulting damage values.
This is all speculation though. But from playing the game it appears that this is the way it is, I could be wrong. If you are going to use netcheat to find stuff you need to pay attention to what is happening in the game and search accordingly.