Hi Gladiator,
I had an RZM M7/36 Hj knife with solid red diamond just like yours, diamond had good movement & was seated a little high in the griplate recess, if the diamond has movement it means it was fitted correctly & if the origional rivets have not been tampered with there is nothing to worry about imo, thanks for showing your hj knife here, we are all living & learning
Regards Mac 66.