I did a search and didn't find any general discussion topic.
These clamps are widely reproduced. I'm interested in those sizes that were typically used on heater, smog system and coolant bypass hoses, so 1 1/16" and 1 3/16" for the 1970 model year. In many/all? cases those that came originally fitted are date coded. Reproductions are often but not always date coded too.
I have seen what I think are NOS items for sale that are not date coded
https://shop.docrebuild.com/1966-1982CorvetteSmogHoseGenuineWittekGN34TowerClampGM9423574.aspx Maybe they are reproductions?
I have seen used date coded examples with date codes into the late 1970s and early 1980s. Did Wittek stop date coding them at a certain point or should every tower clamp that Wittek produced before they went out of business have a date code?
Were original/NOS clamps only ever finished with a galvanised coating? In engine detailing guides (e.g. for Boss 302) I see what I think is zinc dichromate.
Wittek produced these tower clamps in different band widths. Did Ford only use a particular band width?