I believe brick names are stored in .bls save files. You can easily use the brick name instead of the object id or object name.
If you name a brick test, i think test.variable = 1; will actually work, though I might be mistaken.
There's a function that is called when a build is loaded. You can just package the variable storage into the bricks when the function is called.
If you're picky and you want to narrow it down, you can check if the brick named 'test' is the child of a certain brick object you want to use by easily calling an if() statement