Other option of KG-12/13 grips - beside the Baur KG-13B show in this topic:
Cheb2006 KG-13B
https://forum.il2sturmovik.com/topic/23860-kg-13-kbtt-another-one-look-replica/page-2#entry493720- Grip cast in plastic resin Beresin G26 (German components).
- B Knopf holder in metal
- Trigger cast in Nickel
- Buttons cap in plastic resin over base/mechanism of buttons
205K/204K - buttons like ones used in some Russian military grips, e.g. old Mig's.
Here in SimHQ are a topic - done by VO101MMaister about a aluminum cast version of KG-13B sell be some guy - but is not this used in their joystick.
Found it:
http://SimHQ.com/forum/ubbthreads.php/topics/4255604/Luftwaffe_controls_for_simmers