Not that I am aware of but that is nothing I have ever looked at before but will now……

I believe that the clear on the top tells you that they needed more time- were there colored pistils- trichomes are a good indicator but that is really all they are - people have been harvesting long before microscopes were available.
On the main growing forum there are some great threads about when to harvest- read them all before you get your scissors out.
Good luck!