Typically the seat belt data will depend on the manufacturer so make and model will be a big influence. However, vehicles that do not have seat belt sensors will not generate any seat belt data. If the engine is not generating any seat belt data then the GO device will not request or receive it.
Here is an article that has additional information on how Geotab identifies seat belt data: Reporting Seat Belt Data
I hope you find this helpful, please let me know if this is helpful or if you have any additional questions.