IIRC the reluctor can be put on upside down for B/RB applications. It changes the timing so be aware. I think the reluctor has a mark on the edge with an arrow for rotation? Maybe that is on remans only.
Not upside down, but the roll pin that locates the reluctor on the shaft can be put in the wrong slot causing a phasing issue.
The arrow and two lines is where the reluctor roll pin goes for small blocks, and the other slot in the reluctor would be for big blocks. (that way the same part can be used for either small or big blocks)
