Yes, SEP 12.1 64 bit support
use the latest version SEP 12.1 client , which can be used to deploy on 64 bit Servers.
In the Installation package under Admin --> tab ( in SEPM) you can find the install package for 32 bit and 64 bit, use this link to create a package and install
You can auto upgrade 32 bit to 64 bit
You can assign a 32-bit and 64-bit package to the same group when you do an auto-upgrade and both clients will automatically upgrade. You don't have to create separate groups for 32-bit and 64-bit clients