Not a bad text to help you along?...Well I would say that wouldn't I?

Background...
Both the FG-1 (mainly destined for the Royal Navy - later transferred to the RAF) and FGR-2 (RAF version) were derived from the F-4J design. They had the same radar (initially) the Westinghouse AWG-10 pulse doppler look-down, shoot-down capability. The version fitted was in fact a derivative by Ferranti, the AWG 11 and 12.



Getting the serial codes right...
FG-1(K) serials: XT595-8, XT857-76, XV565-92, XT604-610 [FG-1 contract cancelled]
FGR-2(M) serials: XT852-3, XT891-914, XT915-928 [FGR-2 contract cancelled], XV393-501, XV520-551 [FGR-2 contract cancelled]

F-4J[UK] serials: 74 Squadron ZE350-364



Distinguishing the FG-1 from the FGR-2
Apart from the serial code that may not be visible, the other simple ways are telling the two apart are:

FG-1:
- 3 small approach lights (vertically aligned) in nose wheel door
Here are images of the nose gear bay doors.
The FGR-2 up first...


and FG-1...


- inverted slotted leading edge to stabilators
- entire nose cone assembly could be hinged through 180 degrees, folding back on itself for better storage on carriers
- extra extendable nose leg by 40 inches

Both:
- larger flaps, drooping ailerons

- all British suite of navigation / communications avionics and cockpit instruments - in fact front pilot's cockpit is visually very similar to the F-4J - certainly from a scale modelling perspective. Significant differences in rear navigator's position. (see pics in Reference Gallery).
Rear Warning Receiver (RWR) fin-tip fairing was only fitted to the British Phantom family (with the exception of the 15 ex-US Navy F-4J[UK] aircraft.


Stores:
4 X AIM-7E Raytheon Sparrow AAMs
4 X AIM-9 Sidewinder AAMs (AIM-9D at first, changing to AIM-9L in late 1970s)
Here you can see a typical fit of a pair of AIM-9L drill rounds and the SUU-23/A gun pod beneath the fuselage

SUU-23/A cannon pod carried only on centreline station (No.5)- housing GAU-4/A 20mm six-barrelled rotary cannon
2 X 370 US Gal wing fuel [drop] tanks
1 X 600 US Gal fuel tank occasionally carried on centreline station on FG-1 and FGR-2. Usually carried on F-4J[UK]
later from 1977...[fully op 1979]
4 X BAe Skyflash AAMs [in place of Sparrows] externally very similar to Sparrow
No.2 and 41 Squadrons based in Laarbruch, Germany carried a specifically designed recce pod [by EMI] containing cameras and linescan equipment in a distinctive pod carried on the centreline station

Camouflage:
On entry into service standard RAF camouflage colours: RAF Dark Green, Medium Sea Grey over Light Aircraft Grey undersides.
Later from October 1978 XV474 was delivered in Barley Grey that eventually became a mix of: 36314 Barley Grey / 365367 light Aircraft Grey and 36270 Medium Sea Grey.
Various experimental 'lighter' greys were tried out, for example a matt-almost LAG but these weathered so quickly and were not found to be satisfactory. In the final years the Barley Grey became pretty much standard.

Getting that realistic paint finish...


I've included this image of a 19 squadron FGR-2. I love this image, mainly because it illustrates very well the 'waxy', satin finsh very typical of British Phantoms. Some aircraft experimented with an experimental light greay scheme and this was pretty matt. It was quickly withdrawn due to the fact that it picked up every little scratch and scuff! The Barley Grey and green/grey earlier tactical camo scheme always seemed to develop a shiny, but not gloss finish.

Satin varnish is probably the easiest way of achieving this effect, although buffing a flat finish with a soft cloth can achieve a good, satin realistic finish.