The inductors are linearity correction for the scan, though there typically with larger tubes will be some NTC and PTC thermistors in the yoke as well to do wire resistance compensation as well. the magnet offset on the coil is there to make the inductor have variable inductance with current, and yes it is set up for the tube, or at least set up for the tube type, being adjusted in the factory by having a fixed jig with a CRT displaying a test pattern with some chinagraph lines on the CRT face to show the correct linearity, and simply applying the magnet to the coil with wet varnish and turn and move till the lines align with the chinagraph as best as possible, hen remove and leave to dry on a non magnetic board with holes for the leads. This works for small CRT units quite well, as you can have a "typical" CRT used for setup and the producton ones will be close, or just use one per batch as setup unit. For larger CRT's they would hold a plastic printed mask in front of the CRT, and then adjust the linearity magnets, then stick in the small correction magnets ( those little ferrite magnets on long plastic arms that are under the yoke mounts) to get the alignment right and remove colour fringing across the shadowmask, then paint the whole lot in position with varnish on the CRT neck. If you ordered a new CRT it would come with a pre aligned yoke, or with a set of magnets and you had to do all that linearity and colour alignment yourself in a non magnetic area.
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