Torsion bar - odd markings

Ok, I just went out to look at the bars i took off of my car. These bars are considered to be "890" bars, and they measure 0.87" in diameter because my /6 came with A/C. Heres what the #'s look like
UDU UDX One end
891L 890L

891L 890R Opposite end
111 151

I have no idea what these other markings mean!!