Oh, sure, I recycle old ideas all the time in my writing, and I know other writers do too. It stands to reason that composers, like writers, have plenty of leftover bits that they keep in a drawer for when the right occasion to use them comes along.
Interesting analysis of Duning's style. I know that different composers have their own characteristic voices and signatures, but I've never really broken it down in that much detail. (Except for simple things like David Bell's scores for the later Trek shows almost always being in waltz time.)