French Indo-China coin help [solved]

I have just recently started cataloguing my collection and so I'm adding them to the site. As I came across my collection from Laos/French Indo-China, I ran into a problem and I need help. I have two "1 Piastre" coins from French Indo China, 1 from 1917 and the other from 1880. They both weigh 21g, measure at ~3.85cm. However everything I can find online says that the 1 Piastre in Indo-China didn't start until 1885. Is my 1880 coin a fake or is it somehow a previously unknown coin minted before 1885? I've included pictures of both my 1917 and my 1880 coins for comparison and assistance

After the Franco-Chinese war, Vietnam in 1885 completely came under French rule and was divided into three territories with different legal status: Cochin Khin was a French colony and was under the jurisdiction of the Ministry of Trade and Colonies, and Annam and Tonkin received the status of protectorates, relations with which carried out through the French Ministry of Foreign Affairs. Based on the above, it can be seen why the first piastres were dated to 1885.

The counterfeiter helped you, he didn't want to fool you. You know that both are fake.
Blessed be the counterfeiters who do not copy genuine coins

The piastres were not minted in either 1880 or 1917.
1885-1895: https://en.numista.com/catalogue/pieces4510.html
1895-1925: https://en.numista.com/catalogue/pieces11287.html

Actually the weight of the coin is written on the coin itself:
for the earlier type it is 27.215 grs
for the later type it is 27 grs
So your coins are seriously under weight.

The obverse of your 1880 coin (with the weight mentioned as 27 grs) is actually the obverse of the later one.

Unfortunately, the Indo-China piastres are among the heaviest faked coins around. I'm afraid you have two of them.

Thanks all! It's unfortunate to have fakes, but I appreciate the information you all provided, especially ArnoV!