Hello,
I'm glad to hear this will be added soon. I thought it would be good idea to duble check that the 109s get the correct shell ejection schemes because they were kind of complicated as to which models had it or not.
Here is the list:
1) Bf109E-4
Not 100% sure if the wing mounted 20mm MG-FF have it but I think they do because there are holes on the underside by the guns (can somebody confirm this?), definitely none for the cowl guns.
2) Bf109F-4 and Bf109G-2
Only from add-on gunpods, none for the cowl guns and engine mounted MG151 20mm.
3) Bf109G-6 and Bf109G-10
Add-on Gunpods, 2 for MG131 in cowl, none for engine mounted MG151 20mm or MK108 30mm*.
* The Bf109K-4 introduced shell ejection for the MK108 30mm but this was not featured on the Bf109G models with this cannon.
Hope this helps.
Maybe other guys can add in info for planes they know about that migh have complicated shell case ejection differences too?