That does make a lot of sense.
My original question actually stemmed from one of the so called training "myths" that you couldn't preferrentially build part of a muscle like the inner pecs.
If sarcomeres can be added preferrentially to one end, the other, or the middle, then it is possible, and I'd say even likely that a particular exercise could result in more sarcomere density on one end of a muscle than another.
In other words, crossovers may indeed build the inner area of the pec fibers.
Anyway, it turned into a more interesting question I think.