‘Are additions and/or changes to an HOA’s original CC and R’s valid if they are not recorded at the County Recorder’s Office?’
Most CC&Rs have provisions for how they are amended. I would look at those rules first. If they require amendments be recorded, then they must be recorded.
If the CC&Rs themselves are silent, you’ll have to look to the laws of your individual state. If CC&Rs are required to be recorded (as I believe they are in most states), then I would certainly expect amendments to be recorded, too.
However, keep this in mind: If there are amendments that are otherwise valid–that is, everything except recording has been done–then all the HOA would have to do is walk the amendment in to the Recorder’s office and pay the fee.