Prednisone 5 mg verses prednisone 10 mg?

One packet will have 5mg on it and the other 10mg on it usually same apart from mg all depends on what you have been prescribed to take you can get 1mg 2mg don't forget about steroid sick days good drugs if used correctly do not take them willy nilly steroids should be taken as soon as you get up in a morning not spaced unless your doctor tells you too.

Do they have any markings on them, imprint codes?

Images: https://www.drugs.com/imprints.php?drugname=Prednisone

From Drugs.com:

All prescription and over-the-counter (OTC) drugs in the U.S. are required by the FDA to have an imprint code. If your pill has no imprint code it could be a vitamin, diet, herbal, or energy pill, or an illicit or foreign drug. It is not possible to accurately identify a pill online without an imprint code.