Its a model 1911, not 1918. The side panels are correct, so if you do find some nice custom ones, hang on to the old ones. Too bad someone ground off the markings on the frame. Careful work with a small file, or sharping stone, will clean up those buggered screws nicely. Careful work with a sharp awl, or file with a sharp point, could bring out the buggered lettering, but practice on as many other things as you can first.
Nice gun, I have several 11's, a1's, Gold cups, and a few other makes and shoot them all regularly. I love them over any of my 9mm's. Yea, I have more 45's, then I do Dodges, but I'm trying my best to fix that (No, not selling).
Have you checked the serial number, to be sure it is actually one made by Colt? Its not unheard of for people to swap parts.