There is a lot more information you'd need to consider. What size of fenders (youth, adult, long), what width of leathers (2", 2.5", 3"), what kind of leather (roughout, slickout), what color of leather (light, mahogany, black, any one of a million other colors), what kind of decoration (slick, tooled, decorated with silver), etc.
No matter what, replacing them isn't going to be cheap. REPLACEMENT SADDLE FENDERS with STIRRUP LEATHERS | eBay
Or, you could go through a saddle maker and get something that would likely match your saddle better than anything you would stumble across. I honestly don't know if these folks would do just a pair of leathers/fenders, but I know their saddles are good quality and they are great folks to work with. It couldn't hurt to ask. https://corrientesaddleco.com/Home_Page.php