All Spinda have different spot patterns. Well, pretty much. There are billions of combinations, so the chances of ever seeing two the same are pretty much impossible. PKHeX allows you to make any pattern you want.
Some of Spinda's Pokédex entries mention the odds of two Spinda having the same spot pattern as less than one in four billion. Since Spinda's spots are based on its personality value (a 32-bit number), a simplistic model would put the odds at 1 in 4,294,967,295, which is indeed smaller than one in four billion; however, it is actually possible for two personality values to produce spot patterns that are visually identical, so the real odds are somewhat higher.