Track Color Index

It does indeed seem to be an integer.

Have you tried switching your condition to 'custom code' then removing the quotation marks around the number, like this:
self.song().tracks[0].color_index == "4"
Change to
self.song().tracks[0].color_index == 4

If it really is a number then the condition should work without the quotations.. I will try this too when I get a moment.

I just tested this and yes you're correct, color index is an integer.

I will get this updated for the next release (likely to be 2.7.1).
In the meantime, you can do what I mentioned above, switch the condition to custom code and remove the quotation marks, that will treat it is an integer.