Beretta bought Lario out in the 20's... the branding probably ended then as they apparently took all the tooling to Gardone, therefore possibly pre late 20's but it should have a date code.
The FIAT no doubt refers to the FIAT cars of Torino/Turin (T in Fiat) I would say it may be a custom corporate jobbie, maybe for management or owners! - worth the research, let us know what you discover, BTW, this threads worthless without pics and it doesnt exist until you post the pics