There are multiple references to FOB delivery and the associated title considerations in the FAR. See FAR 47.305-2 through -5, the series of clauses beginning at FAR 52.247-43, and perhaps most importantly for your basic question, the definitions for "FOB," "FOB Origin," and "FOB Destination" at FAR 2.101. Those references lay out the rights and responsibilities pertaining to delivery reponsibilities and title transfer for non-commercial items. The issue is simpler for commercial items.  The clause at FAR 52.212-4 (para. (n)) states: "Unless specified elsewhere in this contract, title to items furnished under this contract shall pass to the Government upon acceptance, regardless of when or where the Government takes physical possession."  I'm not aware of significant court rulings on the issue, as the passing of title when using the prescribed FAR clauses is relatively straightforward and not especially subject to differing interpretations.