I just bought a new 6.8l CF tuxing tank and this valve adapter/fill whip https://www.amazon.com/dp/B09D7QC7K9?psc=1&ref=ppx_yo2ov_dt_b_product_details . Common sense tells me that I should put one of those plastic seals behind the fill whip valve, but nowhere in the instructions does it state this. Am I supposed to put a seal in there?