There's no standard per say, but in recent versions of Altium (20, 21, and maybe 19) you can specify the layer type. See:
This additional layer data allows Altium to manage layers by type rather than just layer numbers when importing the footprint into a PCB. This allows you to have different libraries with different layer numbering conventions, and as long as the layer types are specified, Altium will translate the library layers to PCB layers based on the type. i.e. Primitives on the
Assembly Layer from the library will get translated to the PCB
Assembly Layer regardless of layer number.
CAUTION: This is a relatively new feature in Altium and older versions do not support this capability. If you save your PCB or library in an older version of Altium, this metadata will be lost. So, trying to use this feature is not recommended unless everyone in the team is running a recent version of Altium.