Hello Ben. I think the proper lighting is the key. If the text was inscribed into the metal then side lighting may form enough of a shadow to bring out the detail. Then use either of your lenses with an extension tube to get in close. Of course you will want to use a tripod to get as sharp an image as you can. Also stop down the lens to about f8. In PS6 all you want to do is increase the sharpening from the drop down filter menu to enhance the image.