That's not the piece I was thinking of, the one that bolts to the stock rearset on left side?
I think I know where that piece goes that you posted. On the lower part of the swingarm there is 2 bolt holes. However I don't think that there is an OEM piece that goes there? I have 2 675's, one I bought new and one almost new, and niether has a "lower chain guard" like that.