Quick bike question

[PunkA$$]

I realize this isn't the right forum, but I'm not registered on any bike forums and figured I'd get my question answered easily here, so.......

I recently took apart 1990 kx 80 that required splitting the case. I noticed when I split it that there's no gasket in between the two case halves!

Is this the way it's supposed to be with just some form-a-gasket goop in there or should I be searching out a gasket for re assembly?

Thanks in advance:)