i am not sure what is exactly correct material should be however, i think your top should have a slightly fuzzy backing on it,many of the same type of materials are available without backing aswell, but in your case , having a window plug ,the fuzzy backed stuff is more forgiving of imperfections under the top, such as seams,debris, and other issues,a flat non backed material would show every little problem, i have been in the auto upholstry business for about 22 years up until last week, most everything used these days have a backing i have used them both personally ,and its a bit easier to install the fuzzy backed material. good luck!