they dont appear to be knock-offs. those are probably the 19x9.5 +15 and 19x10.5 +15.
http://www.wedswheelsna.com/wp-conte...SA55M_2013.pdf
i forget where they stamp the offset but check on the back of the wheel near the lug bore holes. there should be a "15" stamped on there if those are +15's. at that height and rear stance, i think the previous owner added a 10 or 15mm spacer on the rear.
GLWS