They are generally DB158
I found RUST-OLEUM Painters Touch Ultra Cover 2x Almond Gloss to be a near perfect match for that paint code. Even on my car, which actually IS DB158, you would be VERY hard pressed to see the difference, especially since you are dealing with the inside of the bumpers, and the light just doesn't hit that the same way as the outside of the car. So, my 3 cents worth...unless you happen to have some 158 lying around...go witht he RUST-OLEUM product, and paint right up to the edge. It's easy, almost zero cost and a near perfect match to the point that only a severely OCD stricken judge might notice a difference. Furthermore, most of our cars are not driven in mud anymore, hence they probably most likely won't rust there much anymore after a replate.