If you start from an empty segmentation template then you can set the label values once and those are preserved (if you don’t delete the segment or copy the segment into another segmentation that already uses that label value).
@Sunderlandkyl Do we a helper function in segmentation MRML or logic classes to change associated label value in a segment? (if we keep getting these requests then we may need to expose label and layer value assignment on the GUI and add a flag to allow locking of label&layer for a segment).