It sounds strange, but not like a sting. Cops don't poke around, banging on doors and looking into windows. When I've had stuff delivered, it comes in a mini-van from a private carrier like DHL or a courier service. I don't think they'd come after you. They'd just seize it at customs, and send you a letter that they had seized it. And furthermore, HGH is not a controlled substance in the USA; last I heard, and is available by simple prescription (not the complicated one that sends a copy to the DEA, like some narcotic prescriptions). If you had ordered Adderall, or something like that, they might be more likely to play hardball with you. I bet that car was a private courier, maybe who gets paid by his boss when the package is signed for.
But just a disclaimer: If it's really bad luck, and they are looking into it, don't blame me for downplaying it!
As far as syringes & needles, those are perfectly legal to be sold, owned, and possessed by the general public for veterinary and hobby/scientific use in California, and probably most states. If you have more than 1 element of narcotis or juice equipment in the house, such as a vial of something plus a box of syringes, and you DON'T have any Rx, then it might get sticky. Just as you can have gun powder, or PVC piping, or books on bomb making perfectly legally, but a combination of any of those can be a felony, and you can have a gun in your car, or ammo in your car, but not together.
Charles