Air filter gasket

Good morning. I purchased a 1981 KZ750 LTD H2 this past summer (first bike) and absolutely love this thing. I’ve given her new tires, fork seals, brakes, oils change, plugs and wires, carbs cleaned ( but plan on doing it again). Still have more to do. The chain is maxed, so needs to be replaced.

My question seems stupid but am going to ask it anyway. Is the gasket that “should” sit under the air filter important? Not one there and am having a diff time finding one. Thanks in advance for any help.

If the filter does not seal properly to the box, then dirt can bypass the filter. Also, the missing seal may allow more airflow and turbulence than the carbs expect, giving you some grief in tuning the carbs. I don’t know what that one is supposed to look like, but I wonder if a suitable substitution can be made from some generic foam window and door seal from a local hardware store?