Hi
Yes same plant
Both 351 cars a m code and a h code
Both unrestored and not repainted?
Especially after all these years and with possible repairs parts, especially bolt on ones are replace with "better" ones as owners freshen, repair and restore their cars. Even on a fair number of those "unrestored cars" you see on the internet or in older magazines.
Not saying that we don't find dates at are "out of range" often enough. Could be the one or two that were in the crate sitting at the station that were left when a new batch were bumped in the same crate. Or a new holder was moved to the station and the handful from the earlier batch were tossed into or somewhere in the pile to be grabbed a week or two, later. Add to the mix that you had body style specific panels where a batch/shipment would last longer than say panels that were the same for all body types and produced (for example) in quantities 50 times greater.
When recording dates from unrestored cars its not unusual to find one or two panels out of the hundred or more collected but over all they do tend to form somewhat of a pattern when looked at all the data collected.
