1. Generally speaking, government agencies don't do such a great job reaching out to job applicants, but exceptions are always possible.
2. Pay for government jobs is often competitive in its own way - figuring in job stability, benefits, and pension potentials, government jobs may even beat private-sector jobs. Base salary ranges are formally set, and are not easy to negotiate, but wherever possible, it is always worth trying.
3. Depending on whether the job in question is at the fed, state, or local level, and at what agencies at each level, hiring practice differs in flexibility, timeline, and the selection process (review committee, selecting official, tests, security clearance, etc.). Once you have had a chance to speak with the supervisor who initially contacted you, you would have a much better idea where you are heading.
4. Last but not least, it is not unusual to set clear expectations about salaries at the beginning of a job-searching process. Don't be afraid to ask for clarifications if advertised salary ranges fall outside of your expectations. That way, you don't end up wasting both the other party's time and yours embarking on a wild goose chase that is not leading anywhere.