At this point, no.
V-select converts everything to lowercase before the comparison. You can see this here https://github.com/sagalbot/vue-select/blob/7a2fad6933c81130e5384426c68f0607c7d86308/src/components/Select.vue#L850
If you want to make it case sensitive, and are just looking for a quick fix for your project, you could modify those lines and remove the toLowerCase() call.
Alternatively, if you think this is a prop that should be supported, consider making a pull request and calling toLowerCase() conditionally based on some prop you pass down.
Hopefully that helps. Try making those changes, if you still can't get it to work, post what you tried and maybe someone can help.