Help identifying old Grohe shower valve

[mom2boys]

I've combed the prior posts and can't find mine in there, hoping someone can help me with this as I've not yet heard back from Grohe.
I'm really hoping to be able to replace the trim kit and not the whole shower (which involves breaking into the tile etc.)

 

[Breplum]

that trim kit will not be available from Grohe. And, I don't recognize it as a Grohe product. Grohe never had a lever volume control and never had slotted screws.
you may want to consider re-plating.
Cartridge might reveal mfr better. Symmons used levers like that.