Yep ... my dents are lopsided too. I think it is normal to be lopsided. Our left and right hands aren't exactly the same size, neither are our feet. If you look at your face in the mirror you may even discover that one eye is slightly bigger than the other, or some other slight differences from one side to the other. The vast majority of people are not 100% perfectly symmetrical. I think most are fairly close, and studies show that the ones who are extremely close are considered the most beautiful by societies all over the world, but no one is exact.
And that's the great thing about a Brooks saddle ... it conforms to YOU! You now have a custom made saddle! There's probably no one else out there who would feel comfortable in your dents.
Oh, about your ITBs ... are you stretching regularly?