From the HSCC regs (but will these change for Goodwood?):
All vehicles must have FIA HTP and a Jaguar Heritage Production Record Trace Certificate to which the car must conform unrecorded modifications will not be accepted
. Continuation cars or replicas are not eligible.
Class Structure:
Class A. For Pre 66 specification cars complying with Homologation 100
Class B. For Pre 63 specification cars complying with Homologation 34
So that seems pretty clear cut. Goodwood won't be a decider coz it's not a championship, and I doubt if anyone will be counting anyway 