Centurion helmet from Sisak, Croatia

[Ildar]

I think that the sheet you are seeing wtih punctim is silver not tin. From the description in D'Amatos book, it appears that the rosettes would have been gilt.

Ivan Radman-Livaja. 'Siscia as a Roman Military Stronghold. The Catalogue of Finds,' No. 4. in Finds of the Roman Military Equipment in Croatia. Zagreb, 2010, p. 207:

"Traces of rich decoration are clearly visible on this Weisenau-type helmet, despite the damages. On the lower edge of the frontal half of the calotte a silver band is still well-preserved, while two silver rosettes ornamented with enamel are on each side. During the conservation of the helmet traces of thin silver sheet layers were observed on several places, gilded in some places, and it would seem that the entire helmet was covered in silver sheets. Three different layers of decorative sheets were recognized during conservation process. The first was of silver, decorated in punctuated floral pattern. The second layer was made out of gilded sheets and it is recognizable on few places only, subsequently overlaid with the third silver-sheet layer, also punctuated. It is most likely that the owner(s) of the helmet had it re-decorated on at least three occasions. The silver band on frontal edge partially covers the decorative rosettes, which suggests that this is not an original ornament, but a subsequent addition or repair."