Congrats. Allow me to suggest you take the backsight off and run it through an ultrasonic cleaner with a strong degreaser. I can see encrusted dirt there. Then dry with heat and dunk in thin oil is my advice.
Probably best to take the stock off and remove the whole sight and bridge in one piece rather than fighting with the spring and cross pin.
Worth doing the mag as well as they cannot be disassembled as you know.