The issue with ATF isn't so much the higher operating temperature - it's the high detergent content (that, and the fact that it's so much thinner than gear oil.)
It should be fine. I tend to use a paper gasket only when I do my axles tho - makes it easier to clean the surfaces before I put it all back together, I think (yes, you get gasket stuck to the sealing surfaces. But, it comes right off.)
You may also find it useful to put a stud in the topmost hole, retained with LocTite #242 or #272. This lets you "hang" the cover when you're putting it together - and just loosening that top not before you take all of the other screws out allows you to drain the housing without dropping the )@#($*@) cover into the )(*@#$% drain pain and getting that @#)$(*@)%&* nasty-smelling gear oil all over yourself...