I think she should be allowed Flor. The issue with women going topless is that people don't want to see their breasts, or there breasts are considered sexual. Since she no longer has breasts she should no longer be held to these socially imposed constraints.

Her chest is no different than a mans.

As for going to work topless and walking around. If she works in an environment or is in an environment where men go about topless, than I don't see why she shouldn't.