The Revell kit is, I believe, the old Monogram one from the late 1970s/early 80s; that said it builds well (just watch the join between the lower intake lips and the fuselage/wing).
The RAF bought 15 F-4Js which were reworked and repainted in the USA using FS colour paints. When they arrived they looked like a light blue rather than gray and there is speculation about this being the result of a thin top coat over a green/yellow undercoat. The first a/c to get a , partial, black tail was one which broke down on the way over and arrived late having been got at by ground crew - I think in Cananda but could be wrong. It was a time when the Phantom squadrons took the decision to paint tails in higher visibility colours a bit further than intended and we ended up with 56 and 92 with red tails, 92s boss a/c with a blue tail, the OCU with blue tails and 74 with black (happy days).
The air defence colours for the Phantoms were light a/c gray underside, medium sea grey upper (inner) wings and barley gray fuselage, outer wing panels and tail planes. All to BS standard.
The US equivalents (FS) were light gull gray underside and I believe light stone gray and something else - I think xtracolour did the colours at some point and will try to find my references.
As to the tail - decal onto gloss and then matt down to suit.
A small number of the F-4Js went though rework in the UK and were repainted in British colours; I think 3 but stand to be corrected.
There's a whole section on Britmodeller here:http://www.britmodeller.com/forums/inde ... om/&page=1