The two I have are certainly both ABC's.
Both have totally different mounting brackets (and are different capacities) hence why I'm not going to start drilling holes directly into the floor of the car and using self tappers. The soon as one's use-by date elapses, I'll need to drill different holes to mount a replacement.
How long are there supposed use by dates?
The ones at work just get inspected an re certified. Im sure all they do is check the pin and that the pressure is within range and give it a shake to make sure the powders not set at the bottom