[CentOS] How to determine 64 vs 32 bit processor

I have been tied up with other work and Holidays.  Now back to some 
server work that is long overdue.  I lost an old server yesterday so it 
is crunch time.

I believe my new platform is suppose to be an x86_64.  The order form 
says 64 bit.

I booted Centos 6.3 i386 liveCD to check the system out before an install.

uname -i

reports i386

dmidecode -t processor

reports Characteristics of 64 bit capable.  The processor is an AMD 
duo-core Opteron.

I thought that in a prior thread I found that booting with an i386 live 
CD and using uname would confirm the processor type.  It seems not.

I am going to go with the various evidence and start a x86_64 install, 
but what is with uname?

thanks