I would say that getting a Master's all depends on where your passions lie. If you are passionate about Historic Preservation, and are interested in studying it further then a Master's Degree could definitely be the right choice.
If you are concerned with not being taken seriously with your B.Arch I can assure you that your degree matters much less than your ability to collaborate and do the work asked of you. In reality school prepares you very little for the work that you will actually be doing when you join a firm, and a large part of learning the practice of architecture happens on the job. A student fresh from undergrad will likely be doing the same exact tasks that a student fresh from a graduate program will be doing. I am working at an architecture firm under a licensed architect and did not study architecture in school. I started out doing the same tasks as someone fresh from architecture school. My degree did not matter in the slightest.
As far as licensure goes you do not need a master's degree to get licensed. In some jurisdictions you don't even need a degree in architecture. You can always make the decision to pursue licensure later in your career if you wanted to with or with out a Master's. Check out NCARB's website for more information on the different paths to licensure to get a better understanding of what would be required.
Elisa recommends the following next steps:
- Set-up informational interviews with Architects and Designers who are doing Historic preservation work. Talk to them about their education and career path.
- Set-up informational interviews with Architects and Designers working at firms that you would be interested in working for.