I'm on insider and I got it. They don't roll out to everyone all at once.
Ok, thanks. I was kind of hoping they had skipped the staged roll out with the new accessories likely to be delivered to a lot of Surface Pro 3 owners today, but I guess not. For some reason, it always seems to take a really long time for mine to get the SP3 updates.
Fortunately, I discovered that the driver is available on Microsoft's Update Catalog site. If you go to Microsoft Update Catalog (this only works in IE) and then search for "Surface", the driver is currently the top search result. I was able to quickly get the fingerprint up and running after downloading and manually installing the driver.