After all the trouble I'd had with my order from Mars, I decided to cancel the order and just see what the local store had in stock. I ended up paying a little more than I would have for the one I'd ordered, but I got a really good deal, and ended up with a much better instrument as well.
I had ordered a Squier P-Bass Special 5-string electric bass guitar — a cheap entry-level instrument. I walked away with an ESP LTD B-205 5-string instead, which I got at a shockingly low price because (a) the model had been discontinued, and (b) it was a floor display model, and they couldn't find the box, the warranty registration card, or anything else that had come with it.
From reading reviews, it's apparently considered a lighter-weight bass. My left shoulder finds that surprising, but since it doesn't have much experience with supporting bass guitars, I'm not paying much attention to its opinion.