Trans line question

[Element]

Auto trans, '87 K5 - the hardline coming out of the lower right corner of the radiator is the out/to trans line, correct? Not the hard line located on the same side but about 1/2 way up the radiator? Getting ready to plumb my trans cooler and I want to make sure I hook up to the right line.

 

[Mudstud]

with the engine cold, start it up and feel both lines. The one that starts to get hot first is coming from the tranny.