That most advanced and at the time TOP SECRET bomb sight from the era just prior to the Second World War [WW2], the Norden Bomb sight, still in use during the Vietnam War?
This according to the wiki entry for the bomb sight and this has been confirmed.
"The Norden bombsight was a tachometric bomb sight used by the United States Army Air Forces (USAAF) and the United States Navy during World War II, and the United States Air Force in the Korean and the Vietnam Wars to aid the crew of bomber aircraft in dropping bombs accurately. The last combat use of the Norden was in the US Navy's VO-67 squadron, which used them to drop sensors onto the Ho Chi Minh Trail as late as 1967"
This is only half of the Norden appartatus.
Norden used for the precision dropping of remote Seismic Intrusion Devices [SID's] part and parcel of the Igloo White program as deployed in the Vietnam theatre.
"Tens of thousands of ADSID (Air Delivered Seismic Intrusion Device) were mass produced in three basic variants, supplemented by a range of ground personnel delivered SIDs (Seismic Intrusion Device)."
". . . Initially, most ADSID deliveries were performed by the OP-2E –four heavily modified P-2H Neptune airframes repainted in green, grey or black camouflage and flown by US Navy observation squadron VO-67. The aircraft was fitted with the . . . DIANE (Digital Inertial
Attack and Navigation Equipment) and the World War II Norden optical bomb sight for precision ADSID drops."
From a WW2 USAAF document that entire Norden and as also linked to the planes autopilot.
That P-2 navy patrol plane also from that era of WW2  in the "observation" role during the Vietnam War dropping multitudes of sensors up and the down the length and breadth of the Ho Chi Minh Trail. Sensors the purpose of which was to detect enemy movement and traffic, target and devote same for destruction.
As for the efficacy of the entire Igloo White program, that is still an item for discussion. But almost thirty years after that initial development of Norden, that the bomb sight still going strong and providing an adequate level of performance is quite remarkable.