No, I don't think it does. Very few field modifications changed performance that significantly; most were just the removal of guns for increased turn & speed performance etc, or altering a plane for a different role. Rarer field modifications could require more perk points; heck, with the current LW situation in AH I'd let them have something to even the balance a little.
And I'm talking about field modifications that were really fitted in real life, not fantasy configurations. I somewhat doubt a 75mm cannon could be used effectively on a zeke - what, would it be belt fed?