What Pete said. The only paperwork you get with a mod plate is the receipt for payment.
The mod plate has: The reg number of the Approved Officer who approved everything.
A reference number - which identifies your specific mod approval in the system.
Then modification by: "owner" in your case.
Then the modification codes - these are most important as they tell you what the mod plate is for.
When I look at the pic, it seems to be:
LG2
LH6
LK1
Which means:
LG2 Brake System Substitution (Modification)
LH6 Individual and Low Volume Vehicles (Modification)
LK1 Seating Capacity Alteration and Seat Belt Installation
LH6 is the individually constructed vehicle mod code, which sounds strange, but maybe that was a way of getting the 6" increase in track width approved.
Either way, it looks to me like those codes cover the mods.
Needs quite a tidy up, but looks like a good project. I assume the steering is standard, as there is no LS2 code on the mod plate? ( LS2 Steering Conversion (Modification) )
Something to keep in mind, is that genuine coiler chassis have extra bracing where the the coil turrets, etc are welded on. You may want to check for cracks in those spots, and/or add extra bracing down the track.

