I certainly wouldn't count on it. Ritek G04 and G05's both had very dark purple dye. To be honest I don't think there's any real way to know, especially based on the darkness of the dye.
Try a small spindle or two of each and see which is most compatable with your burner and at which speed the media burns best at. Test your older burns now and again and back-up to different media on signs of degredation.
Can anyone confirm that darker dyes tend to be cyanide based and lighter azo based? Just speculating on a couple of posts I read. Cyanide based dyes have been alleged to fare better in accellerated aging tests, right?
I honestly don't think you can base how long your media is going to last just on the dye though. Fact is, we just don't know because the technology is too new to be tried and tested properly.