I gather from the word 'swing' that was used to sell the 1965 and 1966 Marlin, that the target was Frank Sinatra/Tom Jones fans more than Rolling Stones followers. I think the Charger may have been targeted more toward a younger crowd but I'm not positive. The people in the AMC brochures seem reserved and sophisticated. All of the Dodge brochures for 1966 showed The Dodge Girl, a hip Nancy Sinatra type in a jacket and pants with go-go boots.
This year's Marlin was changed little from the previous year save that it was now the 'AMC Marlin' instead of the 'Marlin by Rambler'. 1965 sales had been 10,327 despite not showing up until March. Full year 1966 sales were 4,547 even though the competitive Charger cost $521 more. That would be a $3,887 difference in 2016 dollars. Radical changes would be needed if the Marlin was to continue.