TD Turbo oil drain line seal?

[JGWarner]

New wrinkle in the TD swap project-

I just had a flicker of memory, that there's a rubber seal that lives in the coupling for the turbo oil drain where it meets the oil pan. A sort of flat o-ring. Am I right or am I going crazy? I didn't put it back or replace it if there was one. This could be a problem, I imagine.