Actually, it is a valid question because even if the library that goes out of business was non-exc, what if you now what to sign the track(s) with an exclusive library? You might have an issue because you are not sure whether you can truly enter an exclusive contract. What if there were placements you weren’t aware of? What if there are still hard drives floating around with your track, previously paid for under a blanket license?
Don’t have all the answers but I would definitely be careful before signing any exclusives for the track(s). Of course, if you only wanted to sign non-exclusives, it’s moot.