There were some very colorful KA-6D color schemes and most of them were A-6A's. One or two of them would have been nice to color the sheet up a bit. Understand you only have so much room on the sheet and it is good to see someone doing decals for the A-6.
Are you thinking of colourful KA-6Ds in the otherwise drab tactical paint scheme A-6E TRAM era, 1980s-1990s? I expect they might follow Steel Beach's announced KA-6D conversion set, or the release of Trumpeter's A-6E Intruder kit mid-year (?)
In the 1970s KA-6Ds were no more colourful than the strikers except for a fuselage band in the relevant ATKRON colour, and white drop tanks with coloured tips instead of explosive ordnance slung on coloured tipped MER racks.
The VA-52 A-6B option on the Zotz sheet Patrick and Eli are working on will have the blue knight and lances logos, crew names, and lances for the centreline tank. You can paint the tips of any bomb racks and/or drop tanks blue, and hang bombs or - specific for a 1972 Vietnam WESTPAC - four anti-radar missiles.
All we need are some decent AGM-78s!