The issue here is the current code is checking for hardware version, Disk Size and a few others the limits the captured MAC image to be deployed only on the exact same machine, otherwise it will fail.
We made some changes to our symdeplomac file to allow for the image to be deployed on more then one model. Attached is the file you will need to use to fix this problem until it is address in a later release.
To apply this fix you will need to replace the symdeplomac file on the NS at this location: \program files\Altiris\Deployment\imaging\Mac\universal\
Once replaced you will need to go to Server manager on the NS, and click Configuration > Task Scheduler Library
Scroll down on the left pane and search for NS.Package Distribution Point right click and select Run, then find NS.Package Refresh, right click and hit Run.
This should update all the packages with the updated file. You are now good to image multiple MAC models.