A belated welcome back, T-Mar, and a thank you for the pic as well--a good reminder that we should all be on guard against chafing.

One more data point: We had a Niko 'Mystere' mixte in the family for a while, a late 70s entry level bike, SN J8A0002. Niko were pretty certainly rebadged Centurions, and this fits the numbering system of Centurion supplier Miki: MyFxxxx, making it 1978 production.