(Helen) I am not at all clear that this alto was made by MK. The key guards are way more modern than anything I have seen from him before. 

They only thing that says "Max Keilwerth" is the Pure Tone Trade Mark MP that would have come with a MK saxophone. 

I wonder if this may not have been a JK-made or inspired horn. Or something made through Heimarbeit? 

Hopefully we will find more of this brand in the future and the origin of this horn will be answered.