The gilded oval clasps are very commonly seen on 20th century Chinese necklaces. I can often ID a necklace as soon as I see the clasp without even clicking the listing. That said, I hear the clasps were sold separately in some places in the 1970s and 80s, so it's possible you might find European beads with Chinese clasps. I have yet to see one however.
I don't know if there is any actual silver content. Perhaps the others might know.
I like the branch with unopened buds. That's a nice detail on your beads.