To Brendon's point, you can definitely use 'cifs shares' in order to get a defined list of information about your shares.
Taking it a step further as well, you can take a look at the contents of /etc/cifsconfig_share.cfg which will provide you with the GUID's which are assigned to the individual shares.
If via using ADMT you migrate SIDHistory as well as the GUID's across, you shouldn't have much of a problem once you cut the filer from Domain1 to Domain2.
Do be careful to make sure and review the list of what you're migrating to make sure that you don't run into any odd duplicates, or end up not migrating over a particular user or group with its respective SID and GUID.
Once you've defined that you indeed have replicated this over, and that the data will match on both sides you can simply point it over to the new domain "Domain2" and if CIFS is configured correctly on the filer (talking to the new domain controllers) as far as the filer is concerned the data populated in that /etc/cifsconfig_share.cfg will not have changed as it remains static referencing GUID's all day long.
Hopefully this helps in what you're doing, luckily (unless I'm mistaken) you're only doing a domain migration and not an actual filer or data migration, so it's merely a matter of resolution and ACL verification!
Let us know how it goes Donnie!
Christopher