I would say thats old enough, we took a brand new u500 to a classic rally once and they just waved us in

but it was an impressive looking piece of kit, had full mulag kit on it front and rear.
I would just send the application of, i doubt there will be an issue, last year there were loads of 110/90 land rovers, and theyre not going to be that old.
Hope to see you there

what model do you have?