Graceland: early mark 3 shells had a two bolt top strut mounting and the turret was a different shape, the two bolts were beside the shock absorber and bolted through the top of the turret, as of 1983(i believe) they changed it to a single bolt so most A cars would have this unless they were early shells that were late registered, but i have never seen a Series one with a two bolt shell as they were too early,, hope this makes sense!!!

if you are ever on e bay looking at pics or at a car show with RS1600i's look at an Y-reg and A-reg you should see the difference