First, we need to tackle the really important question, which is why do you use apostrophes in your numbers instead of commas? Seriously, just curios.
Second, if there is any compensation, I would hazard a guess that it would be a set amount, like $100 per gun, regardless of how much you paid for. But that's just a guess.
I think a more workable and therefore more likely solution would be to first, make all current guns prohibited, and remove the right to pass along your existing weapons to family members. In the short term, no one gets there guns taken away, but in the long term, your children will have to surrender your guns to the police for destruction once you die.