I called the insurance company for clarification, and they confirmed that yes, I would have to pay them back whatever they'd paid out for those items.
So for example, if I recovered my ADAMs I would have to reimburse USAA the $549.50 they gave me for them. For $39 more I could just go into GC and buy them back. Which I most definitely would not do, as they've been beat to sh*t. But if I say I don't know where they are, I can go out and buy new speakers for up to $2,198 and USAA will pay me the $1,648.50 difference. Everybody wins, including the thieves.
I asked the fellow on the phone what motivation I could possibly have to try and recover the items, and he changed the subject. At least he didn't say "because if you had an opportunity to get it back and didn't, we'd sue you."