welcome to INGO.
I know nothing about the training tools you're asking about. IDK about their legality either, but good luck and keep us posted.
Why wouldn't the 1 piece paperweight replicas work for you?
The training grenade in the photo I posted was made around 1940-41 and used to train U.S. Soldiers. It's one piece cast iron and has no moving parts other than the removable pin. I collect original WW1 thru Vietnam Militaria so reproductions don't interest me.