1991- upper intake plenum- no gasket??

Just wondering what is used to seal between the upper and lower manifolds on a 1991 (aluminum upper). There is no available gasket and I could not tell what was on it to begin with after taking it off the lower. I could see what looked like varnish or very hard sealant traces. Did not look like old silicone sealant though. Already put it back together torqued it down after applying a thin layer of high-temp black RTV to the top of the lower manifold surface only. Hope this is ok. Is this thing probably gonna leak or what? I guess I'll find out soon enough.