Is this for an Amex Gold Charge Card or an Amex Gold Credit Card? If the Credit Card, then it makes no difference what the card holders job or income is. The only thing that would be affected by job/income is the credit limit, not the colour of the card. And of course they ability/willingness to pay the higher annual fee (which is often waived these days for various promotions/reasons/criteria).

But the Gold Charge Card has some different scope for spending pattern, so would normally be targeted to people whom Amex deem an acceptible risk, which normally means job stability and verified income limits.

I can only assume these mailings are offered to apply for the card, not an offer for a card.