If you are a collector of Cortendorf, I would be interested to know if all the designs do have the product number stamped on the product.

Model | Year/Era (if dated) | Notes
—– | ——————– | —–
3408  | 1958 (design + launch) | First model of the wall mask line. Female face, Strunz.
3410  | c.1958-59 | undated, inferred by position
3411  | c.1958-59 | undated, inferred by position
3413  | c.1958-59 | undated, inferred by position
3417  | c.1958-59 | undated, inferred by position
3422  | c.1958 | “Frau mit Halstuch”
3426  | 1958 (design + execution stated) | “Frau mit langen Haaren”
3434  | c.1959 | undated, inferred by position
3440  | 1959, produced 1959-1963 | dark-skinned young woman, 3/4 profile; “first wave” of Strunz masks per dealer citation
3446  | c.1959 | undated, inferred by position
3447  | c.1959 | undated, inferred by position
3455  | c.1959 | undated, inferred by position
3456  | c.1959 | undated, inferred by position
3458  | c.1959 | undated, inferred by position
3462  | c.1959 | undated, inferred by position
3466  | c.1959 | undated, inferred by position
3471  | c.1959-60 | undated, inferred by position
3473  | c.1959-60 | undated, inferred by position
3483  | produced 1959-1961 | “Maedchenkopf”
3496  | c.1960 | undated, inferred by position
3603  | c.1960s | RS Raumschmuck branding; ceramic/resin mix noted
3604  | c.1960s | undated, inferred by position
3626  | c.1960s | undated, inferred by position
3627  | c.1960s | undated, inferred by position
3660  | c.1960s | undated, inferred by position
3676  | stated as 1960 in one source — CONFLICTS with sequence position (numerically later than several masks not dated until early-mid 1960s); flag as uncertain
3681  | c.1960s | undated, inferred by position
3682  | c.1960s | also occurs in an “Achental” variant
3683  | produced from 1959 per one listing — also conflicts somewhat with position; flag as uncertain
3689  | c.1960s | “Frauenkopf,” brown tones
3690  | c.1960s | uncertain attribution (“wohl” / “probably” Cortendorf in source)
3694  | c.1960s | undated, inferred by position
3703  | c.1960s | RS Raumschmuck, teak-effect finish
3713  | c.1960s | RS Cortendorf marking
3715  | c.1960s | Lady walll mask with head scarf, inferred by position
3716  | c.1960s | undated, inferred by position
3717  | c.1960s | RS-Raumschmuck, “Maedchen, leicht rechts geneigt, Haarschleife Teak”
3755  | c.1960s, likely later in range | undated, inferred by position


Some important notes
—————————————————–

1. The two dated outliers (3676 and 3683, both cited as 1959-1960 despite being numerically well past models with confirmed 1958-59 dates) suggest the numbering was NOT strictly chronological, or that multiple sub-ranges were allocated in blocks rather than issued in strict sequence.
2. The RS Raumschmuck pieces cluster in the 3600-3700+ range, which is consistent with them being a later phase of the line (early-to-mid 1960s) rather than evidence of a separate factory.
3. Material change: at least two listings describe RS-branded pieces as ceramic/synthetic resin mixes rather than pure ceramic/stoneware — if accurate, this could mark a cost-driven production change later in the line’s run. Single-sourced; worth noting as “reported but unverified.”
4. No model numbers above ~3755 turned up in this pass — doesn’t mean the line stopped there, just that nothing higher surfaced in available listings.
5. Best primary source to chase for a real catalogue/dating system: Horst Makus’s 2000 book on 1950s wall masks. Worth seeing if a copy is findable via German antiquarian booksellers (e.g. ZVAB, booklooker.de) before publishing firm dates.