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They might not be export models. The Raleighs that were to be sold in england kept the chaincases longer than the ones they brought over here.

Chaincase is not indicative of year, plastic is. And brazeons. Look for that stuff.

Roughly:

If they have reflecters on the pedals, then post late 60s.

If they have brazeons for pulleys, then pre 60s.

Color and options don't really count for anything. Check RetroRaleighs for dating.

https://sheldonbrown.com/raleigh.html see that chart at the bottom.

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