Tbh, not sure. I found through google search maybe 2 years apart to 4 year as shown above. There are sites where tou put in your car make and model and it will show you compatible parts. Not sure if i am much help but i will follow, i want some running boards too.
I have running boards on my 19 MDX and the boards replaced a chrome trim piece at the bottom. I think the 14-16 MDXs don't have this chrome trim and that running board in those model years are more plug-n-play. If you are going with OEM running boards, I would download the installation pdf to see what modifications are needed to make the boards fit if you going jump model years.