I take it from the inquiry that you don't have the age related information on the gun or a Type 03 ("Curios and Relics") or Type 01 license. If both are the case you'll need to deal with an importer ($ to $$$).
If you do have the license, I have personally handled many imports under a Type 03 for my own collection so it can be done with preparation and patience. The paperwork has become increasingly burdensome, ironically because of the move to electronic forms, to the point that it is almost necessary to use a broker even though that is not legally required (how many private citizens are set up for ICE/CuBE's electronic system?). The real problem is CuBE ("customs") who seem to change what is needed every six months and at the whim of the particular officer you interact with. ATF is relatively straightforward but you must demonstrate proof of the age of the gun.
Bottom line is if you're set up to do it yourself it can be done.
If not you're best off dealing with importers but pay attention to folks feedback here because some of them are rather incompetent and/or engaged in the personal politics of the gun trade (I write from personal experience) which can create it's own problem. I've had folks hold firearms of mine without notification requiring some effort to track down with the threat of legal action. Make sure that whomever you deal with confirms that they can handle the action from door to door including customs with all parties in the chain identified.
Your state may also have FFL transfer documentation requirements that need to be met. I find these are in practice not an issue if the FFL and Customs are handled in the state where you reside.
Jeremy
