Rather than rely on Internet rumours I contacted Sinclair directly yesterday and they responded today with this:
Exportation requirements for all International Customers
The US Customs Service is requiring an export permit for all orders that include bullets, brass, scopes to certain Countries, and gun parts (rifles, actions, triggers, trigger guard assemblies, barrels, stocks, firing pins, firing pin springs, buttplates, etc.) shipping from the United States. We must apply for and receive these export permits through The US Department of State. This takes approximately 6 weeks for approval. There is an exemption allowing us to ship brass and bullets under 900 combined pieces without an Export Permit. Gun parts also under $100.00 can ship now without a permit.
Sinclair International, Inc. will submit your request for an export permit under our exporting license and forward the requested items to you by the US Postal Service, UPS and DHL no longer accept shipments with the licensed contents. We must have an original or certified copy of your import permit along with an English translation of the permit and your signed order for approval. Your order must include your name, address, shipping address (if different) along with the description and cost of the permit items. These documents are to be sent through the mail as the Department of State will not accept faxed or e-mailed documents.
Due to the paperwork and labor hours involved with applying for the export permits, a licensing fee will be applied to each order. The licensing fee will cover these costs as well as the packaging, handling and coordination of the shipment through the US Postal Service. Licensing fees for orders will be as follows:
Total value of export items under $500 incur a $75 charge
Total value of export items $500.00 - $1500.00 incur a 15% fee
Total value of export items over $1500.00 incur a 10% fee
The above export fees are only for those items that require a permit to ship and not the items that do not require a permit to ship.
