1719 Charles VI Thaler-Mount Removed?

I do not see the mount based on your photo, but I would tend to give PCGS the benefit of the doubt on this one since they had it in hand. The plastic can hide things and I suspect there is rim damage or indentations where a mount was removed. I've seen mounts with obvious evidence of melted metal, and others with small holes (as if something was drilled into the coin from the rim). The worst case scenario is that you break it out, enjoy it raw for a bit, and then submit it to NGC just to have it end in a similar holder. There is not much downside to if you don't mind the NGC fees.

I bought an Italian States piastra years ago in a Heritage auction. The auction description stated that it was mounted, but the PCGS holder did not. It is in a PCGS AU-50 holder which is appropriate. Apparently the cataloguer and the grader did not see it in the same light. PCGS interpreted the metal at 12:00 on the reverse as a Cud, and the cataloguer saw it as evidence of a removed mount. Images are attached. I have studied it under a loupe many times and I have think PCGS was correct. I am fine with my decision to buy and the final hammer was a bit discounted as a result of the catalogue description. Point of the story is make your best judgement and enjoy it for what it is; not everybody will see it with the same eyes.

Here's a link to super high resolution photos by PCGS. Should make it easier to see if there's something near the rim. Too bad they don't take edge shots.

https://images.PCGS.com/TrueView/33212632_max.jpg