These rockers can be identified by their 15.5mm spindle, their rectangular mount blocks of (approximately) 25x25x14mm, and a rocker arm width of 57.5mm.
Rockers have either the Roman numeral 'I' or 'II' cast into the main body; please let us know which you need!
The 57.5mm rocker arm width is wider than that for later bikes, and means its is not possible to directly retrofit later rocker gear to bikes of this period without careful shimming.