hydraulic pump seal

[sama_RA]

On a seal used on a hydraulic pump shaft there is a bright yellow dot marking on the outer diameter of the seal.
Any ideas what it might be indicative of?

[sama_RA]

Thanks. Was my first guess too that the marking indicates aircraft fluid resistant part but was not sure.
Any regulations on ink/paint marking on Skydrol resistant parts? AMS/MIL specs? Color? My search didn't return me any results.