well any painter who properly paints cars will want to blend it into the rest of the panels anyways, so when they quote, they won't just quote for painting the kit, they'll also quote to paint up to fold lines on neighbouring panels. so regardless your quarters will get painted partially, which means you might as well get them pumped while you're at it.
that's how a proper painter would do it anyways, dunno if you get that much attention to detail when you slum it.
if you've ever seen a car with different panels that have slightly different shades or pearls, it's because neighbouring panels haven't been blended. if you didn't do the original job you won't know what colour basecoat was used, what blend was used for the clear, what composition of pearls etc... which is why any good painter will insist on blending.