That the bluestones came from Wales has been know for quite a while, as long ago as when i was in university. Although the link above is much more specific, it has been known for a very long time that the bluestone came from Wales because of the feldspar in the rock. There's a joker named Bernard Cornwell who is a very successful novelist, who wrote a novel about stonhenge a little more than a decade ago . He's one of these writers of historical novels who puts a brief notice at the end of every book to say what parts are historical fact. Well he wrote four novels about the American civil war, and i read the first one. It was utter crap--i didn't bother about the next three. When i read the stonehenge novel i wondered just how accurate he really was, especially as he claimed that the Amesbury Archer was murdered--not just in the text of the novel but in the historical notice at the end. I was pretty sure that couldn't be true--too many grave goods for a murder victim buried to hide the evidence. Why would you murder someone, and then bury them with things like copper knives, which were worth more than gold to bronze age people? So over the years, i have been reading where and when i can. That the bluestone at stone henge was from Wales has been known for a long time, specifically where and how it got there hasn't been known.
There was a long hiatus of new information, but now the Amesbury Archer and the Boscombe Bowmen were all found in this century. There has been a dramatic growth in careful archaeology there in the last 10 to 15 years. When the Amesbury Archer was dug up, the press dubbed him the "King of Sronehenge" (it was a rich burial), and there wa also much speculation, on no very good basis at all, that he was murdered. Cornwell seems to have gone for the dramatic angle, and perhaps relied on his reputation to pull it off. His novels are entertaining, but the historical accuracy is, i think, rarely what he claims.
EDIT: Until i saw the linked material above, i did not know that the specific quarry had been identified. That the stones came from Wales has been known as long ago as the 1960s when i was in university.