My '70 Maico 350 came out with the new sand cast cases but a mates 70 model 400 came with the old die cast 'round' outer cases. I think they were using up what they had left on the shelf. By '71 they were all sand cast 'new design' cases.
I've retro fitted the earlier covers for a more pre '70 look but changed back to the later sand cast ignition cover when I fitted PVL ignition. If anyone has a "narrow" early round die cast ignition cover I'm interested in buying it. The one I fitted is from a sixties round barrel and sticks out too much
see bottom photo). They made a narrower version on '69-70 250s I believe. That's the one I want.