You may order any version, though generic production is many times cheaper due to the lack of promotions, which inflates the cost of a good.
Delivery schedules may vary, but in general USA customers should expect delivery within 21 business days maximum.
The whole manufacturing process is regulated by the US Food and Drug Administration (FDA) and other relevant authorities.
A generic medication is an exact copy of a brand-name medicine, it has the same route of administration, dosage, intended use, side effects, safety and strength.