Welcome Saad,
at first glance it seems that both pieces were once lacquered and for what reason ever, the urushi was stripped. Maybe too much damaging?!
The kabuto has a nice shape. Paired with this Nara-men and the matching tare/shikoro (kiritsuke-kozane) makes it a “set”, one can say…
Estimating age is, unfortunately, not that easy because Zunari-kabuto as also Nara-men were made over a longer time span. However, provided that the shikoro is original to the helmet, the small fukigaeshi pointing rather to an earlier date, backed by the overall shape of the hachi itself.
I would agree with your assumption that the tsunomoto is a later addition. The two holes above might suggest that a narabi-tsunomoto was initially fitted (or the maker changed mind during his work 🤔).