I have a few sets of tank badges for RIIIT (used), RIII Roadster (used) and some carby T100 Bonneville and America accessory versions.
Only the T100 Bonnie and America optional accessory ones are screw mount from memory and were one of 3 options they had, from memory:
Heritage,; Eyebrow; and Classic - all chromed cast metal rather than 3D plastic or just decals.
What are your mount hole center spacings?
Are they threaded bosses or just press fit friction mounts for plastic lug pins on some factory badges?
Other metal vehicle badges can have press fit pins too.
I'll check to see if my chrome metal ones will fit and their part numbers.
They come with a rubber base mat as well from memory.