Suit yourself.
However, I seem to recall that the problem in those disks was that the disk's internal diagnostic does not accurately compensate for the aging of some electronic component.
When the disk "vanishes" for the first time, it is a sign that the component is "borderline" according to the (invalid) diagnostic rule. It will pass the diagnostic when cold, but may fail when hot. As the time passes, the component will get "worse". Eventually the situation may get so bad the disk will not start up even when cold.
The catch is: a disk that is in a "failed" state won't take the firmware upgrade, so if you want to use the patch, you must do it before the disk fails completely.
The firmware patch changes the disk's internal diagnostic rules, so that normal aging of the disk will not cause a failure.
You won't need a HP engineer to install the patch: see the patch description for installation instructions.
If you choose not to run the firmware upgrade, I suggest you to keep your backups carefully up to date.
I think you might survive till October, but you might have to power-cycle the server once or twice during that time to get the disks back again.
If you lose one of the disks permanently, be assured that the other is not far behind.
MK