Tranny Question

I am planning to buy a b16 s1 tranny for my b18. When i go to buy it how am i to know if its really a s1?? Does it have certain numbers on it or the acutal letters "s1" on it??? pleae help

on the front side of the tranny there should be alittel gold sticker that has S1 with soem serial numbers after it. like if the tranny was attached to the engine, look at the engine code then look to the left on the tranny and it should be right there

oh ok thanks alot!!