I think it has more to do with the requirements in the RFP - it REQUIRES a proven hull and power plant in use as a patrol/military craft for a long time - this doesn't exist in the US which means yards have to buy hull forms for their bid from other countries - I think alot of the secrecy exists because of all the foreign deals and lack of the ability of the yards to control the hull design within their own engineering departments.
As far as gifting a contract...that is always a problem with the involvemnt of certain powerful senators from certain shipbuilding states - the USCG historically has been less influenced by political intervention (due to a severe shortage of funds appropriated - no slush hanging around in their budgets) than the Navy.