You'll have issues doing that because the 150 and 170 have different network configs.
You can export the config, clean up the network stuff (e.g. Remove it), and then import the rest to the 170, but you have to be comfortable digging into the XML.
If you get one of the 150s up to the same version as the 170, you can join the 170 to it as part of the cluster, the 170 will get the config. When you break the cluster up to retire the 150, the 170 will keep the config...
Others have just done it by hand, though on the 150s, you can export the various tables (HAT, RAT, Destination Control, SMTP routes, etc), use FTP to pull these files off of the 150, and upload them to the 170, then import them, and then make sure all of the rest is set up...
Check out this thread:
https://supportforums.cisco.com/message/3813047#3813047