This may be old hat to some forum members, but it was new to me and I had a couple of Betas in the early / mid eighties. From a (then) Lancia dealer i got a bit more info. The bulkhead on the Mk 1 saloons was different from the Coupe/HPE/Spider, and it was affected much worse by structurally dangerous rust. So Lancia inspected them and if MOT failures bought them back and scrapped them. I had imagined it was the interest factor that had secured the relatively speaking higher survival rate if coupes etc compared to saloons but it was also the actual difference in how th rust affected the cars.