Correct shoes have flats at the cam end, semi circular at pivot end as normal to locate on the pivot pin. A brake lever measured with a caliper has an overall length of 920mm.
Scrap those safety critical parts....they have the mark of the bodger about them. Brake lever looks a crudely homespun effort, shoes modified to be semi-floating?
Shoes are handed, the lateral offset differs slightly. For the 8"Brake 42 5867 gets you a leading shoe, 42 5868 is the trailing shoe. And yes, they are hard to tell apart!
Swarfy.