Could have been badly damaged, scratched, or dropped. Maybe the previous owner thought it would be easier to swap a new one in instead of repairing the original one. I contacted the gent selling it and he didn't know any info regarding the previous history of the gun. I showed the pics of th egun to the A5 experts on Shotgunworld (now those guys know their guns!) and they were dead certain that was a replacement stock. They also posted pics of an all original 1960 A5 20g and the checkering on the stock was definately different, as was the finish of the stock. Also, the forearms tend to crack more because of improper installation, rather than drying out. There is a small lip on the forearms, and if it isn't perfectly seated, they will very easily crack.