Telling Difference Between L2K v1 and L2K v2

I bought both L2K v1 and L2K v2 and I received them both today. Unscented.

The problem is I can't tell the difference between both of them, since there's nothing differentiating the glass bottles, ie. label wise.

One says 25 on the bottom of the bottle.
One says 36 on the bottom of the bottle.

That's all that's different. Is there a way I can tell between the two?

Thanks!