FWIW, the as the 102.12 parts number prefix indicates that these rings are not for a 102 (2000) model, but for the 2300 model that Alfa Romeo do Brasil (aka FNM) made in the early '80s -- a car that looks quite a bit like a tipo 116 Alfetta Berlina (see this web page). All 102 parts catalogs I have use 1306.18.00x parts numbers for the rings (three types of rings, each one of them with M1, M2, and M3 oversizes).
[SIZE="1"]'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, the car in my avatar, sold as resto project to Austria)
Maintainer of a private 2600 SZ register (not the one in the Netherlands).[/SIZE]