Your vin indicates that the car was built much later than realistic for the bumper guards to be factory installed. They are very unique though and more valuable than the more common ones. Those typically go for $150 and up. So with the rarity of yours, I wouldn't be surprised if they are worth more than three times that. But again, you have to find the person that needs them; to that person, they may be priceless.
And I agree with Chick, make all the memories you can with your son; you can not put a price on that!