Arduino Mega 2560 from .org- which IDE works? My personal choice is to purchase from the .cc (or adafruit) for new boards. YMMV.  Craigslist locally of course has generic and .org boards now and then.

If I get a .org board on craigslist, will I need to use their fork of the IDE for the board to be recognized by the IDE?

My feeling is "yes" but I wanted to confirm.

A board there just now is Arduino mega 2560 from the .org.  Would I have to use their flavor of the IDE?

Thank you for your thoughts- photo of the board I am considering is attached.
Arduino.org and arduino.cc have come to a agreement.
As such all incompatibilities that exist (I don't think they exist for this mega board) will be solved with next version of the Arduino IDE as if it is a board of their own.