NOS is an incorrect term for my parts, since they are not new original old parts, but the current replacement parts that Omega uses.
My SM300 dial, for instance was recently manufactured, and not one left over from the original production. For that reason, there are slight differences between an original and a new.
If you were to send your original SM300 to Bienne to have the case or dial replaced, these are what they would use.
The movement is the only thing original to the era, having been reconditioned.
A watch made of genuine truly NOS parts (ones stockpiled for all these years) would be quite expensive. Don't think I've ever heard of one.