I think I can see the characteristic joint in the leaf stalks, though when I blow up photo 1 the image becomes blurred. Also the other two records on CNM at Rendezvous Creek of Bossiaea are of prostrata rather than buxifolia. An easier character is the colour of the back of the standard (upright) petal - pinky brown to bright pink in prostrata and brown to dark red in buxifolia.