Vermeer M series baler parts

I'm looking for a lead on anyone who would have a vermeer M series baler that they are parting out. I'm looking for the bale shape/equal fill sensors that mount to the tailgate that tell you which direction to drive on the monitor. I've got a 504m that is wired for it but wasn't optioned with it. Tech support says the monitor should pick them right up once installed and plugged in. Unfortunately buying it all new isn't an option right now. Thanks for any help guys!

Vermeer M series baler parts