NEVER go by string pattern alone. Racquets usually have the holes drilled not molded so going by string pattern can result in blunders - Korda has an 18x19 Blade, Dimitrov has an 18x17 PS97, Suarez Navarro had a 16x20 PS ROK.
Steam 100? You can distinguish it by frame geometry and width. If you have a nice angle it's very clear. Maybe it's not as easy as identifying a Steam 99 which has a characteristic shaft and trenches on the inner side of the head but still, please, don't say that it's only distinguishable by string pattern.