I looked a long time to find a Pattern 1903 for my Navy Mark I***.
Finally turned one up.... but it wasn't a 1903!
It was an '88/'03: Pattern 1888 modded to Pattern 1903.
Rifle likes it, anyway.
Moist military stuff, and British especially, generally will tell you exactly what it is and often will give its history.
On British blades, full information is found on the ricasso of the blade: that flat section close to the Guard. Generally you can find the Pattern, who made it and where it was made, WHEN it was made and, of course the Proof mark(X). Some ALSO had formation markings; these are on the Pommel.
Sometimes you will run across a British 1907-type bayonet with a HOOKED QUILLION, very like the Japanese bayonet it was developed from (the Pattern 1907 was called the "Japanese Pattern" when it came out). These will always be a very EARLY bayonet, as hooks were ground off before the Great War. The one I have is a 1912, marked to the Rifle Brigade.
Pattern 1907 bayonets very often are found made by Wilkinson, less often by Sanderson and only very rarely by Vickers. Ishapore are Indian, Lithgow and OA (Orange Arsenal) are Australian.
Hope this helps someone; it's a bit far to drive!