Is it wrong if, as a veteran out of uniform, when the national anthem is playing I salute instead of putting my hand over my heart?

As a veteran you have every right to salute.

It is appropriate, however optional, to salute instead of placing your hand over your heart if you are a vet/SM out of uniform. A recent law made it legal to do so as well.

No you are good. You have every right and I thank you for it.