I think you better add this to line 11 in prorotypes/vierling.lua:

vierling.minable = {mining_time = 1, result = "kj_vierling_nonAA"}

And also this to line 11 in prototypes/phalanx.lua:

phalanx.minable = {mining_time = 1, result = "kj_phalanx_nonAA"}

This way, when you pick up ground versions of AA turrets they dont become their AA variants as they were prior to re-crafting.

Thanks for the hint, but that is actually intentional. This way you can always "convert" the non AA version back into the AA version and vice versa. Since they are basically supposed to be the same entity, but with different aim modes