I doubt that n-butyric acid has ever been used in paint. I think that paint stinks enough without adding that distinctive, rancid smell of n-butyric acid. Most paint manufacturers have spent years trying to make low-odour formulations and that would certainly be the wrong way to go about things.
Most n-butyric acid production goes towards the synthesis of butyrate esters for perfume and flavouring use. It's has also been used as a petrol additive and in the manufacture of pharmaceuticals.
Amyl butyrate (isoamyl butyrate) is a different story. It's been used for years in the manufacture of perfumes and flavouring agents. It's also used in lacquers and some types of paint.
Interestingly, there's another chemical called cellulose acetate butyrate (cellulose acetobuylbutyrate) which has many industrial uses including being used in lacquers and paints.
So, yes, you might well have smelt amyl butyrate in paint products and there is a chance it's in the ghee too.
Having said that, I haven't been able to trace any permissible or known additive to genuine ghee that would account for the fragrant smell. Much effort seems to go into its manufacturer to ensure the purity as oldwoman said. Nevertheless, I can't see why a manufacturer would not try to market a fragrant version if there was a market for it, which clearly there is.
I can only suggest that you contact the manufacturer direct to try to find out what's being added to the ghee. Unfortunately, due to some loopholes in food-labelling regulations arising from incompetance in the EC, manufacturers do not have to declare all the ingredients present in a product and amyl butyrate might well be present.