safe way to build i386 arch makeworld on amd64 arch?

[patrick]

hello list,

is there a save way to 'downgrade' an amd64 build system by using 'make world' ?

e.g. just remove the CPUTYPE=opteron from the make.conf file and do a 
build world/kernels install world/kernels ?

of do we need to do some more for this?

thanks in advance

Regards
patrick