That’s a replica, right?

it is 3.8 grams and doesn’t feel authentic.

Thanks

To be honest I'm not sure. It's surface does look suspicious but it could have just been cleaned and polished. Roman republic coins aren't really my thing and would like to hear from other members too. In any case it's a coin (or replica) of the Papias, they have many different varieties: http://www.wildwinds.com/coins/rsc/papia/t.html

I would compare it to these fakes:

https://www.forumancientcoins.com/fakes/thumbnails.php


I'm bothered by some of the missing features (boarder on both sides), but the weight is correct.

Do you have an image of the edge?

Looks alright to me, but there are good fakes out there.
LRC

In my opinion, it is authentic. The wear, weight and details are okay. You can see that it has been struck and not cast, looking on the effects around some details that are almost impossible to fake (they can be seen especially around the control mark behind the bust of Juno. It was probably cleaned at some point, but seem to be some years ago looking at the patina.
Nonetheless, a last question : how's the rim looking?
That's a coin I would buy if i could get it for a reasonable price.

I also think it's authentic.

One important information that has not been discussed so far but could make a difference: What's the pedigree? Did you acquire it from a reputable collector or coin shop?

Thank you very much.
Here are some more pictures:




About the pedigree, I got it from a guy, who is neither a collector nor a dealer. He knows I'm into coins and approached me to ask if I was interested in buying some stuff he got left from a relative. He sent me this picture:

I offered him a price and said that I don't need the fake US dollar, the Ottoman token, the "fake" Roman coin and the "fake" French 5 Francs. He agreed and sent the coins over. To my surprise, when they arrived, inside the package were also the Ottoman token, the "fake" Roman coin, the "fake" French coin and some additional Austrian silver. The French coin had some weird rust like stuff on it, so I decided from the picture that is fake, but is actually real. Now you think and the Roman coin is real as well. I might need to send him some more money :)

Another thing is this coin:


It looks like this one https://en.numista.com/catalogue/pieces73547.html its the same size, but the weight of mine is 4.5g. Do you have any ideas?

Thanks

In my experience, where there is one fake there is always more.