Sigh, there is no bottle Gestapo to track you down to see if your bottle gun is required to be tested or is out of date. The CF bottles are ridiculously over engineered and actually would have been certified for 30 years but for special interests and US governmental Department of Transportation fear of new technology or 'being wrong could be career destroying' paranoia when they wrote the rules (look it up, it's documented).
As long as you do not expose the bottle to extremely high heat to damage the 'plastic' or subject the surface to physical damage that disrupts the fibers it is very strong and has basically zero failure rate around the world (the 2"/50mm). The safety factor is higher than it actually has to be compared to other pressure vessel materials. That's why the regulations don't require pressure vessels under 2" to be tested as unnecessary for public safety. The slightly larger bottles are basically the same and unless you are a hair splitter, don't worry about it.
As per the repurposed SCBA bottles, as long as you fill with your own compressor the law does not apply, only at a commercial or governmental (ie fire station, etc) does the date need to be checked and complied with. The date also applies to 'transportation, commercial or governmental but NOT PRIVATE so you can transport these (filled) in your personal car and it is 'legal' {don't leave ANY high pressure bottles in a hot car!!!!!!! Steel, aluminum or CF. Look up pictures of car explosions with tanks}.
Note the strength of the CF composite goes down as temperature rises but as long as a threshold is not reached the strength returns as it cools. Normal temps of houses and what you would have outdoors using it is very much in the high strength range. Beyond the temperature limit the bottle is permanently weakened... and inside a hot car or trunk on a hot sunny day when the inside temp can reach 160+ degrees is borderline weakening temps, especially if it happens repeatedly.
Further note that CF composite can be weakened by UV long term exposure but who leaves their air rifle or fill tank in the sun for weeks and months?
Finally, the real danger to CF bottles is the aluminum liner and moisture in the fill... which is why you should have AND MAINTAIN a desiccant in your fill system. This is what the five year internal inspection is looking for before the hydro (I used to work in a hydro shop and have done thousands of bottles)
