I am fairly new to all the collector jargon but from what I have been able to asertain the 2 colored caps signify limited edition strikes.
All strikes do NOT have the same amount minted.
Casinos place these strikes in the colored capsules as a chaser in the machine to get us to play longer in hopes of winning one of these more rare strikes.
As far as fakes, I imagine that a less scrupelous operator may place a common in a colored capsuel. I have read that this does happen,but personally I have never experienced it.
Hope my little bit of this helps.