There are pressure/vacuum relief valves near the top (in the stepped area) that would be on the bottom in your application so they may not function correctly. If they function when inverted, they could let water into the battery pack if you drive through water deep enough to reach them. Also, as you noted, the safety disconnect would be on the bottom and might need some protection from road debris.
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL Plus purchased 8/10/2019