1920 Fat Man Dollar PMD Or Otherwise?

Yes, looks like PMD on the rim, and harshly cleaned.

Damage yes, but any thoughts as to whether this is a rough test cut to assess the silver content?

I think it looks like a cast fake.
When or what cause the damage who can say?
I deliberately damaged some of my cast fakes just to expose the insides.
Maybe wrong, been there before.I have my doubts.
This piece should be 39mm, .890silver, 2 1/2 mm thick and weighs 27grams

@mac, for my Sigma (which looks similar to the OP's), the silver settings are: 99.99%, 99.9%, 92.5 % Sterling, 90% US pre-1900, 90% US pre-1945, 90% coin 1960, 96% Britannia, and 80% Canadian.

I'd like to see a crystal clear close-up of these marks if the OP can provide them.

For the most part, classic USA silver is 90% silver with the other 10% being copper.
Specific gravity can support that.
The coin in the OP could have a mix of quite a few metals (maybe as much as 11).
If silver, as the gadget shows, my doubts remain.
Take the reading on the gadget.
Then see if specific gravity is 10.31
I appreciate the close-ups of those odd marks.
I snapped a bunch of those when making this binder:

No but I could post some photos.
Some critics would say I am tipping them off as to what avoid to improve their fakes.

Short story. I remembered my in laws acquired 2 of these Fat man dollars, when someone living in the same village decided to sell their family fortune, having good amount to sell and raise money for whatever causes of their own matter. My in law bought these for 100 yuan a piece back in the mid-90's, about $15 US dollars each with current exchange rate, not knowing if these were genuine or not, it later came into my possession once they knew I collected coins, and I had these 2 coins today still reside some place in my albums.

This post had raise my curiosity when reading Albert comments, if the possibility of genuine Fat man dollar had used various alloys mixed in when many of these were strike, beside the silver content, the lack of quality control back then would be questionable.