ASME B16.20 Spiral Wound Gasket Centering Ring Material Abbreviation

I have some metallic spiral wound gaskets here that have only the centering (outer) ring,no inner ring. The ring is carbon steel. Should this ring be marked to show the material grade (CRS)? I can't find where it's required.

ASME 16.20

Metallic Gaskets for Pipe Flanges Ring-Joint, Spiral-Wound, and Jacketed

3.4 Marking

3.4.1 General. The centering ring of each spiral wound gasket shall be permanently marked. The lettering height shall be a minimum of 2.5 mm (0.1 in.).The following information shall be included with the centering ring markings:

(a) manufacturer's name or trademark.

(b) flange size (NPS).

(c) pressure class.

(d) winding metal abbreviation (see Table 19), except that the abbreviation may be omitted when 304 stainless steel is used.

(e) filler material abbreviation (see Table 19).

(f) centering and inner ring metal abbreviation (see Table 19), except that the abbreviation may be omitted when carbon steel is used for the outer ring and 304 stainless steel is used for the inner ring.