Oh, that's the VIN for a 1966 MGB!! Here ya go:
MGB codes start with 'GHN' which collectively mean 'MGB roadster'.
& here they are individually:
G = MG
H = 1400cc to 2000cc engine
N = 2-seater tourer
L = Left hand drive pre-1967
80304 = 1966, probably around February
You need to figure out what the MGA numbers are because if you don't, that MGA just became valueless - & not as in "mucho dinero" but as in "nada"! In other words: WORTHLESS to a collector! & if its a coupe, well.......
So, if you can't find the original VIN, you need to find a '60 MGA data plate!