Is this authentic? I've never seen an OMAS nib of this era (with this imprint) with a round hole...the imprint quality looks subpar. Is this some sort of contemporary or later fake nib?? Or prototype nib? (The pen looks very authentic otherwise)

omas 555_s with strange nib.JPGomas 555_s 2 with strange nib.JPG

(current ebay link: https://www.ebay.it/itm/403091101301...torefresh=true)