Ralph Lauren Corp. said on Tuesday it expects to face higher shipping and commodity costs in the next few months as the high-end apparel maker is spending heavily to ensure stores are stocked with its Polo shirts and sports jackets during the holiday season. The New York-based company’s shares fell 4 percent in morning trade even after the company raised its full-year revenue forecast. Unlike its European luxury peers, which manufacture the bulk of their products in their home market, Ralph Lauren sources the vast majority of its offerings from outside the United States, with 40 percent manufactured in China and Vietnam alone, making the company more susceptible to shipping delays and factory closures. Those supply chain disruptions have especially hobbled the clothing industry, with apparel having the highest online out-of-stock levels among U.S. retail sectors in the run-up to the holiday season, according to Adobe Analytics. However, Ralph Lauren …