11 and 12 cabs

[paul Lincoln]

Can any of you "small detail" gents help me out with something that has cropped up during my research, please?
On studdying various photos of LRDG Ford F30 trucks (starting with the one Kuno rediscovered) I noticed that most have the pull switches on the dash boards. They also, nearly, all have the "over the bumper" type of tow hooks. I spotted that one vehicle in a photo has the later swivel tow eyes.
Is there a date cut off for either of these features, or were they fitted as available? Did any 12 cab models get fitted with Marmon Harrington axles, or was that a strict change over along with the cab type too?
Any informed help would be much appreciated. thank You.