[WFBowen]

IMO someone either replaced the rear lid/grille assembly or, as mentioned, changed the emblem to the block style. This is not uncommon, as rear lids get their share of banging around or folks just wanted to update the look. It's not too common for someone to change a dash emblem as they're not easily removed without scratching up the dash deco.
Regardless of what emblem is on the back, it's a really great looking 912.
Bill.