Sure can. It's a common misconception that tritium has a colour - in fact, it's colourless and the lume colour depends on the phosphors that are doped with the tritium. The same goes for SuperLuminova, they can alter the chemical mix and the dyes used to give a wide range of different colours. In fact, it's surprisingly wide, take a look at the Luminova colour chart:

Not sure what colour the black ones would luminesce! Reminds me of a line from Hitchhiker's: "Every time you try to operate one of these weird black controls that are labelled in black on a black background, a little black light lights up black to let you know you've done it."

As for date, that serial is in the first batch of 7753s I have records for, so I'd be tempted to pitch it as more likely to be '69/70 than 70/71. Chances are it's 1970.