The skin is mostly covering the part of the shank where there is not so much meat. So I think it is probably fine to leave it on for smoking. The skin, bones, and weird pieces of meat can be used to make a delicious stock for beans, split pea soup, bean/ham soup, potato/ham soup, corn chowder, or anything where you might use a bacon base for flavor. Boil ham trimmings, skin, bones, and scraps for an hour or two, then pull any nice meat bits off that you can, and reserve for soup. Return bones and odd scraps to the pot of water, and boil for several hours to extract every bit of flavor out of those bones. Strain the broth and freeze until needed. I refrigerate the stock overnight, then scrape off the fat layer on the top, and use the fat for frying potatoes, or anything where you might use bacon fat for frying, including frying your aromatics for soup.
