As suggested by Jays you shouldn't read too much into build numbers. My own view based on a couple of factory visits is that they generally are built in sequence but delays with extra's, non-standard paint finishes etc. can put them out. I suspect in Kirk's case there was some re-cycling of a build slot number allocation as well.
Lee who built my car #83884 went on to build #83871 but that was maybe explained by the three layer paint finish spec'd. I saw built up engine/transmission units labelled with build and week number. In this case it was started four weeks later.
Last edited by Richard Wood; 30/05/16 12:47 PM.