Not sure what later seat brackets you are referring to? Up to 9/72 the left seat was designed to be removed quickly with no tools. After that seats were held in with bolts. Of course those would be a much more solid installation. But if something breaks and doesn't get repaired that blame falls on the operator. When I bought a one owner 1970 FJ40 in 2011 one of those latches was broke. It was replaced.
I always like having some tools in a cruiser. If somewhere with the top and doors off it is nice to have a lockable storage that's out of sight. When I installed bucket seats from a 74 FJ40 in my 68 I modified the left front driver's seat mount to be outside the tool box and still have the lid and lock. On any newer than a 9/72 I sure wouldn't have the factory tool pouch inside an open 40.