I will tell you why I am suspicious of the first coin:
The fact that the coin's surface is rough, should be a result of oxydisation or, in
rare cases, rusty dies, The wear on the coin is not equally distributed, sharpness of detail is lacking everywhere.
Second, and much more difficult to notice is the
style and execution of the coin: Trjan 's nose is not
good - there are no examples with a
sharp pointed nose like that. The eyebrow is totally different from what you might expect to see on Trajan's coins. Some letters look too modern to me. When I see so many things that strike me, I grow very suspicious of a coin. Forging is done by meticulously copying an original (casting) or by making new dies. For the last, you need expert skills as you want the new coin to LOOK like an original. When you are not an expert engraver, you might want to make the new coin to look like it has been in circulation for a long time and is partly worn.
Other
members might want to add something to these thoughts, but I am very much in doubt.
Frans