I know that when shipping items into the US from other countries, wether or not you have issues with customs tends to be a matter of luck, and at least in my case, which shipping company you use.
I sent my cue from Japan to the US to have the LBM ferrules replace with ivory. My cue got hung up in Alaska for having ivory ferrules, and a monitor lizard wrap. The ferruels were not ivory, and the wrap was a pressed pigskin, but the customs officials wouldn't budge. I was lucky to have the cue shipped back to me instead having it confiscated.
Everytime I've shipped with FedEx, I've had some kind of trouble with customs or duties, however when shipping with EMS, I've never had that kind of problem. Of course, both times with FedEx, I've been honest about the value of the contents, and the times with EMS, I undervalued the total value of the contents, so that may have made the difference.
dave