Did the UK build GT40's, mk1 & JWR and the Shelby build, Holman Moody build, Alan Mann build & Karkraft build all have their own ID tags?
Or was it just one, just the same ID tag for all.
How about mk2 & 3 & 4 ?
All the "GT40" tubs were built by Lola/Ford (GT/101~GT/105), or FAV (Ford Advanced Vehicles) GT/106!Gt/112 and production chassis P1000~P108?
using Tennant panels. I believe all the chassis left England with the "Ford" ID plates.
the MK-II chassis were shipped incomplete to Shelby American at LAX for completion by the various race teams, Holman-Moody, Alan Mann or Shelby American. There are photos suggesting during this process the cars may have gotten new ID plates, and later Holman-Moody added their ID plates to MK-IIB modified chassis and also chassis later rebuilt at HM.
all the J car / MK-IV chassis received the plain Ford ID plates at Kar Kraft.
This could all get quite involved ! very involved....
The production (eg, GT40/P1xxxx series) cars carried 'FORD ADVANCED VEHICLES LTD' chassis plates (the LTD is stylised, the base of the L continues underneath a slightly smaller , but still capital, T & D) or alternatively 'FORD MOTOR COMPANY' chassis plates.
That is until the FAV factory & production rights were transferred to JWA. (not JWR)
JWA had their own chassis plates on which the GT40/Pxxxx numbering system continued as before. These plates usually read 'J.W. AUTOMOTIVE ENGINEERING LTD'. (some plates have an additional full stop before the letter J & also spell out LIMITED rather than LTD. In addition the type face is slightly different on these ones.)
Any chassis plate mentioning MKl, Mkl, MKll, Mkll (a or b), Slough, UK, etc is a modern interpretation of a plate or a Superformance continuation car.
The original chassis were made by Abbey Panels Ltd.
Tennant began producing replacement chassis in the 1980's or thereabouts.
As you suspect, the individual race teams did what they wanted with chassis plates ! Complicated at the time & by now most have been rebuilt or restored, some with original plates & some with new or reproduction plates. Period photographs are the way to go but not many people would of photographed chassis plates in the 1960's !