Employment letter for a bank

Some banks in Latin America require a formal-looking "carta del trabajo".

I've managed to open a few accounts with it; however, I no longer have that job; Yet, the "employment letter" can be very easily edited in order to feed the local bureaucracy.
My employment letter is for a company elsewhere, not in the US, CA, not in the EU. A bank will unlikely to call my job; let alone that a bank won't be able to speak the language.

Q:
Law-wise, would it be a big deal to edit the ex-exmployment letter, to present it to a bank as a recent one? As I know, in case of doubt, a bank will simply refuse to open an account, say "good bye" in the evaluation period, rather than to take a more radical action - forward it to the police?

---

Generally, what a gibberish. If one has a job OUTSIDE OF the country, will it mean that all the money that one receives on a newly opened bank account will come that job in particular, hence clear? Those banks assume that yes. Or perhaps they themselves could care less, as the employment letter will serve as a proof for a regulator?