Silver tennis pendant

So this is the latest addition to the collection. I found this vintage tennis pendant for 1,5€ in a thrift shop yesterday. Thought it could be silver and indeed, it is. It has a 800 stamp on its back. I loved the design right away. Must have been from someone who really loved the tennis game. I don t know anything about the game, but these two brackets look ancient to me. I think the pendant dates to the twenties or thirties.
The red stone could be a small garnet. It depicts the tennisball.
I also noticed this beautiful pair of cufflinks. They miss some of their enamel, so I got them for free.
I wish I could Kyratise them ;-) some advise on them would be appreciated.
So, do you think I m right about the pendant, it being from the '20 s or thirties?
Hope you enjoy!