if it's a dead trademark, they can't claim any protection for it.
The registration status is one thing. Actual use of the trademark, if any, is what matters. Whether or not they kept up with paperwork at the USPTO is not determinative of whether they have legally enforcible rights.
Look at it this way. You can own a dog. If you don't renew your dog license, it doesn't mean that you don't have a dog. So, let's say I am thinking of breaking into your house at night. I check the local dog license records and see that your dog license has expired. "Aha", I say, "he doesn't have a dog." So I break into your house, and your dog wakes up and bites me.
Now IF the mark is no longer being used on goods and services, then they may have abandoned the *mark*. Abandonment of the application MAY indicate that they've abandoned the mark itself. But what matters is whether or not they have an enforcible mark, not whether or not they have a federal registration.