As someone that has worked with multiple different HGH factories, I can attest that the color of the tops are just about completely meaningless. Usually a batch of HGH raws will be turned into thousands of kits, and the supplier puts different color tops on them. I've been told it's so sources can stay consistent with the color, to avoid any customer confusion. Now there are some suppliers that stay consistent, and say put 'x' color for 100IU kits, and 'y' color on 150IU kits, etc. As a general rule though, it's almost completely superfluous. Sometimes it's something as dumb as they ran out of a certain color of caps lol. As a consumer you should really just pay attention to lab testing, and perhaps the vaccum/lack-there-of when you add the bac water.
There are a lot of factories and not all of them do things the same way, but that's been my experience.