I have hardback editions from the OUP and Walck. The Walck edition's dust jacket advertises a number of later Sutcliff books, through "The Mark of the Horse Lord" (1965), so this may be a late 1960s reprint. Likewise, I can't be sure how old the OUP edition is.

Both editions are identical on these points:

1. Aurus and sestercia.

2. Campagnion.

3. Hypercaust.

4. Mamatine.

5. Agripensis.

In other words, it looks as though it was an editor at Farrar Strauss & Giroux who made the changes.