Both rims are true, it was new with .8 hrs, so no chains.The spacers are on the front only. My guess they are there to add extra room between rim/tire and steering joint.I would like to here from other BX1500 owners if they got them.
If you go to Tractorsmart.com and download the parts manual for the BX1500 [forget how, but it is available I'm pretty sure] you could look and see if spacers are standard on the front end of the BX1500...
If so you would have your answer...if not, maybe you could ask your dealer why they are there on yours...