The windshields are all the same for a particular coach. They each have a number on them which is used to order the proper windshield for installation. In most cases, if possible, they reuse the old rubber gasket. The variable in the whole installation process is the fiberglass front cap. IF the hole was cut properly by the factory AND the front cap was molded/designed properly, then the windshield SHOULD fit and seal tightly.
Perhaps you need to check to see that the correct windshield was used when the change was made. IF they brought out the wrong one, no one will be able to get it to fit right.