That is correct, main difference is around exhaust area (including a deeper fuselage) and the intakes, but there are a few more.
Nose gear is different and could extend by an extra 20" or so - at least on the F-4K. I suspect the nose cone may be larger, but I could be wrong there.
Top of fin is different on some and there are different types of stabilizers.
Unfortunately, I have yet to find a set of drawings that depict all changes correctly in any scale.
I was disappointed when SAM Publications book on F-4 Overseas Operators did not include any drawings at all of the British Phantoms!
I did start on a set myself at one time, but time ran out and I have moved three times and doubt I can find them now.
My book (Osprey Air Combat) states
Length 57'7.1" 17.554m
Span 38' 4.9" 11.706m
Height (fin) 16'1.0" 4.902m
Track 17'10.9" 5.458m
/Sten aka modelerswede