Say you were changing the rear cassette from one(badly bent)wheel to another.
During the transistion you slip and drop the cassette. The resulting sprockets and assorted spacers go flying.

Is there any markings to line them up correctly or would they just slip back on randomly and be ok?

This is purely hypothetical you understand 😳

they will only go on the right way

Just put them on in size order with a spacer between each sprocket. Largest nearest the spokes. Smaller sprockets have a built in spacer. The sprockets should only fit on the freehub one way. Oh and any lettering on the sprockets faces towards the frame.

Yes one spline is wider than the others…

They only fit on the spline in one angular position, but the spacers can go anywhere between them, you just need to get them evenly spaced, its usually a block of 4 or 5 with a built in spacer, a gear,spacer, gear, spacer then the final two usually have a built in spacer as part of the cog.

As above, theres a 'long and a short' spline next to one another and the sprockets can only fit on the freehub when correctly lined up, tooth No. stamping facing outward.

😳

Ahh i see it now!

Kept looking at the sprockets…….didn't spot the odd spline on the hub-meaning they will only fit the 1 way! 😕

Hypothetically you understand 😳

Thankyou………..i'll lower the dose of the stupid pills i think!