I have a Lemans blue with lemon vert. Definitely a yellow color but I can see why folks would mistake it.
I rarely wear jeans, but my belt does stain the seat. I found a perfect match for the color in the towel section at Kmart. I usually keep the towel on my seat. Works perfect and is also nice of I'm sweaty from the gym.
My only issue is that recently a squeak has popped up at where the outboard adjustments are. The leather runs the plastic there under some conditions and squeaks. I'm hoping that using some cleaner will also "lube" the rub spot.
You can see the discoloration line here: