My question involves criminal law for the state of: Ohio

I'm a witness in a felony theft case. The item that was stolen was a catalytic converter valued at $2000 by the prosecution (cost to buy a replacement from the local dealership), and the anything over $500 is a felony.

The defense is taking it to trial arguing that the 'value of the theft' should be the market value for a *used* converter (instead of the new replacement cost) because the converter was not new when it was stolen. The market value of the item would be less than $500.

Questions:

1) Which method of valuation is correct? New (from the dealership) or Used (from a junkyard)?

2) If the judge agrees that the value of the theft is below the felony level and finds the defendant not guilty (bench trial) then can the prosecutor file again as a misdemeanor case?