squeegeesunny,

Look at the cog and chainring closely. They are often (unfortunately not always) stamped with the information you are looking for. Of course, to get the tooth count you can always count them manually. The 1/8th 3/32nd question is a good one. Obviously, 1/8th chains are wider but if someone didn't know the difference how could they tell? Even if for example the cog was stamped 3/32 there is no rule against running a 1/8th chain. Of course, if you have 1/8th anything (cog or chainring) then you are at least guaranteed the chain is 1/8th. Again, good question.