The big question is how much do you like the care there overall? I always think that it's interesting that people equate cost of care with quality care. It's not always the case. I know that I provide exceptional care to the kids I have in my daycare, and I also know that I am mid-range in price. MIne is a home daycare vs a center though and I don't have the same overhead and since I had to have my kids in care prior to running my own daycare, I like being able to provide quality care to families who may not be able to afford daycare easily.
Back to your question. Whether you're over reacting (imo) depends on how many kids are there, how many babies are there and how many caregivers are there. One baby item looks surprisingly the same as another and it's easy to get distracted, set something down and then forget which child it goes with. My daycare is not big and I'm really familiar with my kids, and I have a good system so I tend not to lose things. But I don't think it should be a deal breaker. I'd talk to them about your concerns and see if it improves. I would point out that you are careful to label things so they don't get misplaced and mixed with someone else's things.
I would be bothered by some things like pacis in her cubby. If they aren't keeping track of which paci belongs to which child then kids are probably sharing their germs and illness will be more frequent. No fun, especially with an 8 mo old.
I don't really have an opinion about whether your over reacting because it's hard to see the whole picture... just some things to consider. The care she gets there might be great and the lack of organization with "stuff" may or may not be an indicator of the quality.