Could these be rose-cut diamonds? (plus hallmark help)

I wonder if that thing has been rebacked. The front and setting look far older than a rollover clasp would suggest.

 

Hi Ownedbybear,
It is wonderful to see you posting again. You have been so missed.
Thank you for making my Thanksgiving off to a great start.♥♥♥♥♥♥
greg

 

Bear's back! This is the first bear I've welcomed into the neighborhood since ... ever. And yes we get the four-footed variety.

 

I blow kisses to all. And hugs back at Greg and Don, obvs!

 

Hi Quirky, I like your pin! I also have an antique pin with diamonds on it.They do look like yours but mine are bezelset and opened backed.I was told they were actually cut by hand before the rose cut became popular.I will try to add a picture if I can!Interested to hear what you find out!