We ran into that on Dells at the office. There is no electrical difference. It's the paint on the keytops. After the change you change the keyboard or language/region in Windows. Since that is well discussed I won't write about that.
Has anyone changed the AZERTY keyboard on a french HP Pavilion dv7-7190sf with a QWERTY one? or vice versa. Can it be done? Are they the same size with the same fixings?