Howdy!
I just don't get the whole premise to start with.
If you are CC'ing the firearm, how would the local law enforcement types know you're carrying any magazine, let alone one that might be questionable.
If you are carrying concealed, that means they'd never see it anyhow.
Then again, this forum is supposed to be about Open Carry; hence the name "Open Carry dot Org".
Meanwhile, ....
Unless you've gone out of your way to attract attention from an LEO, there should not be an issue.
I assume you are not passing through with an intent to buy pot or attend 4/20 activities, because getting high and handguns have no business together.
The new Colorado law regarding magazine capacity applies to citizens of Colorado.
How can it be applied to folks who do not live in Colorado?
That doesn't make any sense either.
You're passing through, and carrying concealed, it should never be an issue.
Everything is legal until you find some LEO discovers an opportunity to bust you for something.
My suggestion is; don't borrow troubles you don't need anyway.
Blessings,
M-Taliesin