Jd 450b gear 3 and 4 numbers ground off

so I own a 450b and the 3 and the 4 numbers for the transmission range selector are ground off of the plate next to the shifter leaving only the 1 and the 2 showing. The 3rd and 4th gears do work as the should. I have ran across another 450b that had the same thing done to it and I would like to know why this is done? Any ideas?

Jd 450b gear 3 and 4 numbers ground off