The pattern of the animal does not indicate genetically if it has one or two copies of the pinstripe gene, I could be wrong, but I believe the OP simply pointed out the pattern because he liked it.
Its not really "easy" to breed for super or homo pins, because statistically you would get 1 in 4 animals as a homo pin (assuming 25% chance for normals, 50% chance for pins and 25% chance for homo pins); however, unlike the super form of co dominant animals you cannot tell what you've produced visually because all three pins look the same. To breed these animals and get them on the market the only way would be to take all three pinstripe animals and raise them to breeding size and then breed them (realistically multiple times) and look for an animal which produces only pinstripe offspring.
One season may be enough for a male animal if you pair him to multiple females; however, should you have selected the wrong animal you may have wasted the breeding potential of many females for the season. If you hit a homo pin on a female you will need to breed her for multiple seasons to "prove" her genetics are not just luck. The only time an animal like this could be sold on the market is as an adult, or as the offspring of two proven homo pin adults, but let's be honest, most people wouldn't buy a baby Super Pinstripe. Short of raising these for your own collection, there's really no practicality for producing them for the market, even if producing some supers is "easy".