Depending on where the little buggers chewed, you can replace the forward section of the gasket with a common "top bulb" edge trim from your local hardware store.
e.g.
13 x 8 x 10mm Toolbox Seal With Top Bulb Rubber
https://www.bunnings.com.au/goliath-13- ... r_p4230049

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You'll need to cut the factory gasket at the point where the two types are welded together and install the new top-bulb in-place of the old one which has often rusted.
If the mice have chewed the rearward part of the gasket (closest to the windscreen), then this product won't be a direct replacement.
I don't know where to source that style from sorry.