Historic Preservation masters degree?

I'm in the Mid-Atlantic US and considering a Historic Preservation masters. I have a B.Arch degree & am (recently!) licensed. I'm working in a firm that does some historic work along with other project typologies. I plan to get involved in my city/surrounding areas historic committees, but does getting a historic preservation masters make sense to get? Is it necessary? Do I need it? I'm very interested in historic work and found a program I'm interested in - but curious to hear from other architects who work in historic sectors. What do you think?