While the original idea was of a Supertrooper squad (or something), Lucas changed his mind and merged it into a single character: BOBA FETT. This image shows clearly the change:
View attachment 194246
We see 5 helmets here: 2 unfinished, 2 partially finished (trimmed and painted?) and 1 dented helmet almost finished. The 6th helmet (or the 1st) was the finished, undented Supertrooper helmet. This image was taken somewhere in June-September 1978.