Carburetor Gasket Question

Just received my new exchange carburetor from Ly-Con.
Came with two gaskets, one is black and the other a reddish-brown.

Both identical as to size and hole pattern.
The brown-ish gasket appears to be slightly thicker than the black.

Any comments as to which gasket goes where?
(Top vs bottom)

Carb is an MA4SPA.
Standard Vans air filter assembly.
RV4

Thanks!!