There is probably no way to know for certain short of analyzing what else came out of the same excavation layer.
Roman nails were hand forged iron and almost all have square or rectangular shafts. They could have small round
head, wide round heads, or rectangular heads.
All your nails look like
Roman ones I have seen - but they also look like nails made and used by 18th and 19th century pioneer settlers in Upper
Canada, where I live. I expect almost all pre-industrial nails looked almost the same.
SC