There were no gold on my caps, only the pins.
I think that the gold on your piece is worth many times more than the PGM in the pins. Just use a hammer to smash the porcelain caps so you only have metal left, then if you want to do it you could melt it down. Do it in a fume hood or outside with the wind blowing from the side so you get no smoke in your face. Dental stuff can be contaminated with mercury and it's always best to be on the safe side.
If you're only after the value, just melt and sell it. You might not get the value of any PGM:s included but the XRF should reveal to you if there is any significant amount in the alloy. Just check with the buyer if he pays for PGM:s and if he have any lower limit for payout.
Göran