They should
I've dealt with CZ-USA, fortunately never for repair needs. Their communication/organizaiton skills aren't perfect. Mike can be a little gruff but is usually helpful. When I've ordered from them, it is clear that they don't always have their sh*t together. They are still way better than EAA.
They had firing pins for my 86 Cz75. Why they wouldn't have them for the other... don't know. THough I think 1999 falls into the first few years of the firing pin safety.
The thing with CZ-USA, as far as I can tell, is that they are a seperate entity from CZ-UB (who actually makes the firearms). The CZ factory in Czech Republic probably has any part you could possibly want. I think not stocking those is simply an oversight on the part of CZ-USA.
There does seem to have been a run of guns with extraction problems. CZs are my favorite pistols, but I'll admit they do seem turn out more lemons then Glock/HK/SIG, but this is reflected inthe price and CZ-USA has been decent about correcting problems. I've never had to use their warranty though.