Is a concept of good and bad innate or learned? Some people would say that without religion, there would be no moral code to tell us what is good and bad.

Some Darwinist's like Dawkins say that acts like sharing and feelings like guilt are innate and that we don't need religion. And that we can have morals without religion. He gives the examples of a monkey sharing it's food. 

However there appear to be some religions, e.g. human sacrifice in paganism, or death for apostasy in Islam, which seem to suggest that the notion of what constitutes good and bad is more flexible. And the feeling of guilt would be more a social construct.

Sure we can have laws without religion. But these laws might just suit the majority not the minority.

So for instance would a person who had never been taught that murder is bad. But that murder as a revenge for steeling (for example) is good. Would they then feel guilt after comitting a murder? (As Dawkin's might posit). Or feel like they have done a good deed?

Thus, from a psychological standpoint, is Dawkin's correct in thinking that humans would be kind to each other in the absence of society built on the foundations of a religious code. If so what exactly is "guilt" if it only exists with respect to social expectations.
Psychologically, guilt can be described as "a feeling of responsibility or remorse for some offense, crime, wrong, etc., whether real or imagined" (Dictionary.com).

Guilt is an emotion triggered by a belief that you did something wrong, based on what you think is wrong. You can feel guilty after breaking your New year resolution. You can also feel guilty when doing something what is considered wrong by social, moral or religious criteria set by others but only when you believe that what you did is wrong.

So, you can feel guilty when you do something against your personal beliefs. I'm not answering to "Is a concept of good and bad innate or learned?" because, this is not a psychological question...The question what is innate and learned, of course, can be a psychological question. I believe that the capability of feeling guilt (not guilt by itself) is innate.