Sounds about normal to me! I had a 55 Chevy pickup farm truck with the same brown streaks--I wadded up newspaper, soaked it in lap cement (tar) and stuffed it into the inside of the eyebrows as backing. Once it "dried" I covered the outside with Bondo and painted the whole thing with a Hudson (brand) hand pump sprayer using enamel house paint. I was 15 yrs old and thought it worked/looked great! Lots of fun miles in that old truck--makes me want the '55 Skoolie all the more!