Impossible to value without any more information.
FN is one
You will have to carefully note exactly how the gun is marked, first.
12 gauge Belgian Browning shotgun, serial #296305
It's a Belgian gun, the ELG is a Belgian proofmark.
The barrel will be marked "Made in Belgium"
Impossible to answer.
This shotgun is in the neighborhood of 100 years old. There is fairly extensive information online available on this shotgun.
One of innumerable guns imported from Belgian from around 1880 through 1910 for the catalog/hardware trade. Value would be below $200.
That is a Belgian proofmark, but would need to know the other markings on the gun in order to identify it.
50-10000 USD depending on specifics.
Yes