I'm guessing it was bought by a collector and hopefully the price reflects it's rarity. I know from hanging out at Deere specific sites that certain attachments bring BIG bucks because there were not many made. Examples for the 300 series tractors are the rear mounted ground saw (ditch witch type device), the front mounted PTO driven elec. generator, and the rear mounted post drill made by Danuser back in the early 1970s, among others.
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