It cannot tell you the bag is authentic. Serials are printed on a patch, and a patch can be reproduced. What a serial gives you is a consistency check. If the format does not match the era the bag appears to be from, that is a reason to look harder at the construction, the hardware and the lining.
It cannot tell you what the bag is worth. Condition, colour and demand decide that, and none of them are encoded in a serial.
For anything expensive, have a qualified professional look at it in person. This is a reference, and a reference is a starting point rather than a verdict.