Nope erle, I just went to my garage and double-checked the length on the stock shocks on a friend's BA who keeps his bike in my garage(he only has a carport at his home here in Prescott) before I answered Martin's question here, and they were 13 inches alright.
(btw..I didn't measure my shocks 'cause just a little while back I got me a GREAT deal on some slightly used 412s from Pinwheel that somehow became available right after a little incident happened at last year's Nelson/Kootenay Rally!...yep, it seems the guy who originally had 'em on his bike somehow found himself lyin' in a London hospital bed in the year 1943!!!)