It would be quite a worthwhile exercise to do a timeline chart with the shell detail changes for Mk1/2/3.
The tefal heads could blind us all with their info,as long as they were willing to 'share the knowledge' !!
I could start by listing some '59 features,I'm not sure when they were deleted so any '59'ers out there
please add the dates :-
No bulkhead hole for air intake hose
No recesses for front and back windscreen
Larger depressions in front footwells
Flat outer sills
Single thickness A-panels
Square drainhole at sides of doors
Little raised dimples/pyramids on front panel
Different front seat mounts that are welded to crossmember
Starter button housing is a separate panel/different shape
Front floorpan fitted underneath toe board
No roof gutter drip rail
Small drilled holes in roof gutter
Bonnet prop 'stay' vertical instead of horizontal
Other Mk1 detail differences I can think of
Hydro pipe clips (Sep 64)
Seat belt mount position on B post (high -> June '63)
3 different designs of sunvisor (1. single central hinge 2. pivotting corner type 3.Later crushable with pivot each end) 1. -> Sept '64 2. -> Dec '65
Captive nuts spotwelded to front bulkhead for later plastic binnacle (Late '66)
Later front panel gets cutouts at bottom corners for better brake cooling (May-July 64)
Bootlid changed to double skin type (Dec '66)
Nipple shrouds (ooeer) deleted (?)
Piano hinge rear 1/4 window frames changed to 2-loop hinges and stainless frame (less holes for hinges in shell)(Aug '67)
Safety boss added to door handles (Jan '66)
Thank God for the Parnell Bible !!