Yes, in my limited knowledge Sekine would use both head badges in the same year, used to denote the lower end and higher end brands. Although the red Sekine would be a newer model than your green one (and I am still green with envy with that find) and possibly an 80's model since it has the stem shifters rather than on the down tube.
The rhinestone HB would be for the low to mid range bikes and the medialle HB for the higher end bikes.