The rpm implementation does not control what strings are used to identify arch in packages. For example, PLD is using "pentium3", "pentium4", and "amd64" while Red Hat is using "i586", "i686" and "x86_64" with essentially the same meanings, and all of those strings are being carried in default rpm configuration.
The pentium 3 is definatly a i686 arch... the p2 and pentium pro as well...