GDP growers & purple strains

Noticed some purple tinge & purple veins on the underside of the leaves (GDP) at 6 weeks veg. Has anyone noticed this in their purple strains? Is this a good sign for purple buds? Looks really cool, but potency is most important to me.

As I recall the veg plants had red or purple stems, leaves were normal. The plants with less purple were no less potent or good. This was GDP.

Mine look the same. I'm not expecting purple plants but I wouldn't complain if they turned out that way