Poly,
I've had my FL CCW for 8 years now, although it's only semi-recently been valid here. I think the positives far outweigh the negatives in the FL vs. MO CCW debate.
You should still be good to go as far as the carjacking goes as you still should be legal when carried in your vehicle (not sure on the age restriction on this). You just wont be able to hang out at the local "stop and rob" at 2am , "waiting for the shit to go down".
Although I'm not a fan of the 7 day waiting period for HG permits, when other Sheriff Depts can work the permits in 10 minutes, JCSD has been very good to me as far as class 3 firearms go. There is nothing better than walking in, in shorts and t-shirt, and having them sign off on a Machine Gun or SBR, like it's no big deal.
Good luck on your MO CCW issue.
scottMO