Essentially yes, however it must be noted that you should go at least see your doctor for a chat if you need them regularly. If you have a condition/something about your body you didn't know, its going to be a miserable day when you take the wrong kind/too much/etc and become ill, low body function, or worse, (i.e die). If you just want to take a few on a hard day to get some sleep, it typically is perfectly fine.

It is safe to take over-the-counter sleep drugs, as long as one is not is not taking those drugs with other drugs, and everything else is in order. Whenever you're taking a drug, you should make sure it is appropriate for your state of health, and that it does not interfere with another drug you're taking.