If you go to sandbox and choose research all technologies or run command /c game.player.force.research_all_technologies() the vanilla gun turret gets 420% damage bonus instead of 230%.
Tried researching all technologies in editor by doing the shift click to instant research and the bonuses were correct (230%) so I assume in normal play it should work fine.
Indeed! More powerful gun turret MK-2 gets 230%. In tech branch both turrets get the same bonuses every tech. Probably some other branch adds bonuses to MK-1 occasionally.
And in the end MK-2 has a very small advantage in damage per bullet vs MK1 turret - 260 vs 200 for piercing ammo despite having x2 multiplied damage. Therefore expected MK1 damage should be 130, not 200.
Maybe I shoulde note that by:
"Tried researching all technologies in editor by doing the shift click to instant research and the bonuses were correct (230%) so I assume in normal play it should work fine."
I meant ALL technologies not just gun turret related ones not sure if that was understood corectly. (Also possible there are some hiden ones that the console still gets but that is just wide speculation from someone with almost no modding experience.).