$2K for a fully operational BOP in good or better conditon would be on the high side.....but not outrageous. $2K for a "fair" condition BOP with wear and needing work is ludicrous.
Here is how I look at this machine & sale. The seller is pricing this machine as one in good or better condition. By doing so, they have an obligation to show potential buyers the price is commensurate with the condition. This is done by showing good photos, complete with detail.
At least thats how things are supposed to work! In the real world, things are less than perfect.
You'll be overpaying at $2K. How much is a guess without fully knowing the condition.