Just for future reference, the 1964 note Concerning... 'The Hoard' has this to say on Beren vs the Dwarves:
The "Necklace and the Silmaril" here are not separate, of course. This is following on from the version of the ruin of Doriath, and as far as I know this seems to be Tolkien's latest view, since The Wanderings of Húrin material is dated by Christopher to the late 1950s (it's written on paper dated to 1954/57).
Fugitives from Doriath brought news to Beren in Ossiriand, especially of the rape of the Silmaril. He gathered a force and waylaid the Dwarves on their return march, at a ford across one of the “Seven Rivers of Ossir”. Then the Dwarves were routed. The gold and silver was cast into the river, which hereafter bore a new name, signifying ‘Golden-bed’. But Beren rescued the Necklace and the Silmaril. Lúthien wore it, until ere long she and Beren passed away and were heard of no more in Middle-earth.
The "Necklace and the Silmaril" here are not separate, of course. This is following on from the version of the ruin of Doriath, and as far as I know this seems to be Tolkien's latest view, since The Wanderings of Húrin material is dated by Christopher to the late 1950s (it's written on paper dated to 1954/57).