Dare I equate this all to semantics, i.e. just a difference of words rather than underlying opinion?
You are saying a scientist doesn't believe in quantum mechanics even though he "accepts" it as being "true."
What do you call belief then but the acceptance of certain things being true?
You say in your OP that beliefs are fixed while models and ideas are flexible.
However, I would say that even though a belief might have a short shelf life, it doesn't negate the fact that it is still a belief. A scientist in my mind is someone who uses a certain methodological process for determining what is true. This methodology often proves previous truths false and the scientist naturally tends to develop a heavy cynicism in his language.
(My favorite book on cynical language btw is called Quantum Psychology.)
Anyway, for example the scientist will say something like "based on the best available data right now, this appears to be true." By phrasing his belief in this way he exposes his assumptions allowing the truth to be flexible should the assumptions prove faulty at some future point, however, in the mean time these assumptions are still operating in the belief. He still believes quantum physics is true until his assumptions are proven false.
Then you'll have the alternative. "The Bible is absolutely true."
This is a belief as well, however, the assumptions are hidden from language and therefore awareness. There is no tying of the statement to some scientifically derived formula though, so the assumptions will likely go unchallenged, and therefore there's no real need to explicitly state the conditions upon which the belief rests.
I think this is really an issue of language and the process of truth finding. Scientists and skeptics use some sort of underlying empirical process for their beliefs, and therefore those beliefs are always subject to change when new data arises. So called dogmatists have beliefs that aren't subjected to an empirical process and therefore don't need to change.
However, the same belief structure hard coded into the human's mind is being used. Think of it like the CPU and computer software. If you were to replace an old program with a new program every single day, it wouldn't mean the computer isn't still using underlying machine code. The CPU is just looking for some code and it will execute it. Likewise your mind will execute your programming the same whether it's modern science or writings from the cults of ancient egypt.