Help needed identifying serial numbers

[Toys R us 1]

Hello am new to the site I have recently purchased a 520H with 300 hrs on the engine I would appreciate it if someone could explain the ID numbers for

me.The ID no.is31200E02.     20230.         #9048. Any help would be appreciated

[Achto 29,420]

 

Here is a Wheel Horse master list. Your tractor is a 1989 model.

 

http://www.mywheelhorse.com/graphics/file/wheel_horse_products_master_model_list.pdf