Glad to hear that my History in Motion article was an inspiration.
Modification Instruction C-30-471-00/CF-002 directed that the spare tire be relocated from the cargo box to the where the tool box was located in 1983. Here is a photograph taken in Valcartier in 1984 showing the change, I did not photograph any of the M813A1s during RV85. This image may also answer your tire question.
