One slot could become the Me 410B.
Generally the B-variant had 1 pair of main armament guns changed. MG 17 -> MG 131.
Book: Profile - The Messerschmitt Me 210/410 Series wrote:Production of the Me 410 was rapidly increasing by this time and several new variants were introduced. The Me 410B-1 was essentially similar to the A-1, but with the nose-mounted 7.9mm MG 17 machine-guns replaced by 13mm MG 131 weapons.
Wikipedia wrote:The Me 410B-series was similar to the A-series but replaced the pair of 7.92 mm (.312 in) MG 17s with 13 mm (.51 in) MG 131 machine guns.