@3490lmt
My best guess there is that you've enabled to show hidden items locally for the nuvi 50 folder when it was open, but then the changes haven't been saved universally, so you then can't see hidden files and folders for your 3490.
Unhide permanently via Control Panel>Folder Options>View, enable the radio button for 'Show hidden files, folders and drives'. Click 'OK'.

140.bin is not something you can 'see' in the unit. It's a backup or copy of a particular unit's non-volatile region 140 [rgn140]. Please read the other thread already linked, but quite frankly i'm not sure what you'll achieve because I believe dasilvarsa is correct and ecoRoute should be available to your 3490 [Main Page 'Where To?/Map'>Apps>EcoRoute and you can set up your profile. However, in some localities it's not free as OEM and you may have to make a purchase of the App.

Your nuvi 50 is not capable of using ecoRoute.