[Closed] can you tell different weight oils apart

I know it sounds like a stoooopid question but I recently bought some lyriks, and they come with a first service kit included (unklehomer approves), and there was some sram oil. Only the oil says reverb on it, but doesn't say what weight it is. Looking at it in the bottle it looks pretty thin and I'm pretty sure its thinner than 15w red rum stuff, but is there any form of test I can do? other than poor it out next to some 15w and poke it with a stick? I have a reverb, so can put it to good use if that's what it is... either they used a generic bottle for the fork oil, or gave me the wrong oil.

cheers all.