1980 Gazelle (64cm) with 90s Campagnolo Athena groupset. Possible tourer.

As you mentioned in the other thread, the most likely answer is that you have an Italian threaded HS with a 26.5mm crown race.

A frame that passed through my hands had an ITA HS fitted to ISO forks: the steerer had been peened (correct term?), using a punch at an angle to raise the surface at intervals around the circumference.

The race was secure and I'd guess it had been used like that for some time (Seventies frame); I wouldn't like to say whether this is preferable over a shim.

"Staked" is the term you're after. I did this to secure a crown race after re-cutting the fork with a tool that cut just a tad too small. It seemed to be secure after fitting and has given me no issues. I'd prefer it to coke can shim just because it can't fall out. As long as you stake the race all the way round it should remain reasonably concentric.