O,sorry, no its not a sandcast its a verry early diecast, but wit a lower number than the bookes say.
For the Netherlands its suppost to be a number higher than 103**** but i own a bike with a lot lower number than that.
And i also own other bikes, one has a number starting with 1009*** its a USA import-bike, i did buy this bike in the states and take it to the Netherlands last jear.
It neads restoration, it has matching numbers starting with 1009*** that means its a verry earley diecast-bike.
Its from 10/69.
I do own more Honda CB bikes, from 125 twin to the CB 750 '69 (and 3x K0 '70, and K 1 '71 and CB 750 K2 '72).