Hey GeekGal...

Yes... The HV battery DOES Indeed take up space in the cavity where the Full Size Spare should be. Now... is it too much space? Not sure. Because of the HV Battery, the spare DOES sit lower to the ground.

Crawl under there and take a look. A picture is worth 1000 words.
If a full size spare goes on there, it will hang down and show below your bumper.
If that's OK with you, then fine, go with it.

I'm also not 100% convinced a full size spare would actually fit properly, with the coolent line and everything. You may be able to gerry-rig it... but it won't be a factory type fit.