If you need the GX7 one, I found this in the DP Review .... copy and paste here:Ya, secret menu, like play Nintendo/PS secret code unlock...
Probably I shld start an sticky on FAQ/tips on oly cameras, if it helps.
Here's how for GX7:
With your camera's battery well charged, perform the following steps in sequence:
Insert a memory card into the card slot;
Turn the camera ON and take a picture;
Select single shot mode;
Turn the camera OFF;
Press and hold simultaneously the DISPLAY, AF/AE LOCK, and RIGHT ARROW buttons, while turning the camera ON;
Now, press and hold the AF/AE LOCK button together with the MENU/SET and LEFT ARROW buttons;
Repeat the last step, that is press and hold the AF/AE LOCK button while pressing the MENU/SET and LEFT ARROW buttons. A two-page operation history display will appear;
Press DISPLAY to toggle between the two information menus;
Write down the number next to PWRCNT. This is how many times the camera has been powered up;
Write down the number next to SHTCNT. This is the shutter activation count;
Write down the number next to STBCNT. This is the number of times the flash has fired;
Switch the camera off to revert back to normal operating mode. Congratulations, you have successfully retrieved the shutter actuations information!
copied from http://www.apotelyt.com/photo-camera/panasonic-g-shutter-count
Hope that helps ...