Any surface coating you put on unfinished wood (that is a toy), will have to be tested by an accredited (by CPSC) 3rd Party Testing lab. The sealer, finish, paint, stain, etc. needs tested. The lab will provide you with an analysis report so you can type up a Certificate of Conformity for your trucks. The branding iron will work, with your business name and place of manufacture and then get a date stamp to stamp date of manufacture.