Pics would help to verify the style of S/S wheel you have. The 68-69 styled steels were not used on Any 1970 cars to my knowledge. The 12/69 date is a little late to have been factory installed and suggests to me that they are a service replacement made not very long after Ford stopped installing them on cars. This style of wheel was used on Mustang, Fairlane, Torino, Ranchero in 68-69 and even 69 Cougar Eliminator. The Argent versus Chrome Centers was dependent on car model and options, such as Sprint, GT, Mach1, Etc. Argent was definitely used on 68 Sprint B Mustangs for instance. There was even period literature that showed the availability of body color painted centers (ie: Red or Blue, etc) on the 68-69 S/S wheels. I have seen a couple cars with them painted but not necessarily from the factory and I am not sure how many, if any, cars made it out with body colored S/S wheels.