This plate is attached to the flap control box on the right wing. The first component of the serial number, 683A, denotes the Canadian Air Force CF-104 version built by Canadair under license. Extrapolating the Lockheed serial number, 1151, in the batch of 200 CF-104 aircraft, produces CAF tail number 12851. The assumption is that 12851 would have been delivered with this wing installed. 12851 is displayed at the Aalborg Defence and Garrison Museum as R-851. Presumably there was a wing swap during the aircraft's service career.

The base part number 785771 shows up in the generic F-104G-4 parts catalog as Structure Assembly, Box (presumably wing box). The rule of thumb with Lockheed part numbers is that odd dash numbers are left side and even dash numbers are right side. This -506 part would be the right wing box structure. The reference to TO 1F-104-1052 identifies a TCTO (Time Compliance Technical Order) that was probably a structural upgrade to the wing. The TCTO is somewhat like a Service Bulletin and has a finite compliance time requirement for all affected aircraft to be upgraded.

The first component of the serial number, 683D, denotes a Canadair-built F-104G export version for MAP (Military Assistance Program) countries.

It came from a batch of 48 F-104G
MSN 6001-6048
USAF Serials 62-12302 to 62-12349
Source: Baugher (RIP Joe)

MSN 6042 is USAF serial 62-12343.
It was delivered to the RDAF on 19DEC64 as R-343.
R-343 crashed on 08AUG80 with the loss of the pilot. Clearly this wing was removed from the aircraft prior to this. Source:
http://www.916-starfighter.de/F-104_RDAF_serial.htm

This plate is attached to the left wing box.

These two abutting plates are fixed with adhesive to the attach fittings of the left wing.

It is likely that there is a similar Royal Danish Air Force plate on the right wing but hidden by the wing fillets.