Does this come with the gasket. What is the part number of the gasket if I need to order separately. Thanks

This venturi does not come with screws and gasket. Please check to see if the burner you order comes with them, it will be listed on the individual burner page. If not, the gasket sku is SHK4 - https://grillpartssearch.com/product/SHK4.html
Depending on the manufacturer, some burners come with gaskets and some venturi come with gaskets. You can always give us a call if in doubt and we will be happy to answer your questions.