Is there a website that shows what the different coil spring paint daubs mean?
Mine are white - brownish red - and light blue.
You'll find that the white was not part of the identification marks but instead a mark added after that step to identify those springs that measured outside of the expected range. Instead of tossing them Ford workers would match up two of the same springs (in this case with the white stripe) and put them on the same car so to not cause an issue. You should be able to tell that the white paint was applied differently (ones I've had and seen did) than the other two.
No site has posted a complete list of all the different combinations but build sheets are the best resource for this info. MPCs often list replacement part markings rather than original ones and spring marking did sometimes change during a production year so look for examples built around the same time as your car
Don't see any in my buildsheet collect with a blue listed but don't know how your car is equipped. Do have a picture of one for a 68 with a blue stripe but its a service part identified by the part number C8ZZ-5310-C. No second color visible in the picture