Sometimes it's just better to go to a true stick-and-brick store so you know for sure what you are actually purchasing. It might cost a little more, but at least you know it's right when you come home with it.
If I need parts or replacing something, I go to one of two local dealerships and get it there. If they don't have it in stock, they'll order it. I can either pick the item up there or have it shipped to me. I prefer to pick it up at their store. In dealing with parts and such, in 20 years of RV ownership, I've never had a problem.