What size inseam to you wear (jeans)?
I got mine last week as well, same color and model. I needed a 38", but they sold them in 36" or 40". I bought the 36" and I think they will work for me, but they are a hair short. I did talk to them and they are willing to exchange them, despite what the website says, but I'm afraid the 40" will be a little long and might be an issue in the field. Since I have chainsaw boots, I think I'm probably going to stick with the slight short 36" chaps.
As a side note, these things are pretty thick. I'm not sure how often I'll wear these in the heat of the summer, but they should be comfortable in the cool weather.