I think I'd look for a new lawyer depending on how the trust is set up. If assets go directly to listed beneficiaries on death and you die tomorrow your kids do not get MG's since they are prohibited due to age (I assume they are under 18) That's a problem.
On the other hand, again, no one comes looking for your guns unless there is a complaint filed/reported. I've had a MG stolen and ATF does not pursue these cases even though I told them the last known whereabouts of the firearm. I had a friend who had one stolen as well. The process is you report it stolen, they add it to their database, and if it's recovered and called in by another LE agency they will take action then. You have to doggone hope to heck they get the ser. # correct as another friend is trying to get one of his guns back but there is a discrepancy in how the serial # is read in terms of a prefix. So far he hasn't gotten it back and the perp is being held on other stuff but won't be charged with stealing the gun.
If they were to go looking they'd start at the transferee's address. If the accompanying form for responsible person does not bear the name of the person in possession, I'd guess something is going to be confiscated first, then maybe sorted out later.....this would be a best case scenario. Worse case, trustee is dead, no secondary trustee to transfer the gun out, no other responsible person listed, high legal fee's to court appoint a new trustee to facilitate further transfers. Trust may or may not exist depending how is written/executed.
Most every estate I've seen with MG's is a mess. Discussed one this weekend with a dealer friend who is holding estate guns he purchased and logged in at atf's request, but the executor is sick of dealing with it and will no longer sign any forms. These guns will be cut, but fortunately they are only a couple thousand total.