Not in the 80s and 90s it wasn't. Up to about the fifties or early sixties your 1-11 numbering is correct, but by the sixties, 4-4-2. 4-3-3 or whatever, messed it up through having two centre halves (CBs to you these days) not one. 'Traditionally' the two centre halves became nos. 5 and 6 (no.4...