The experience I had was enquiring about getting a green book for my grey bike CB400SF.
I had got the bike to like new condition engine 7 years old frame 8 years old.
Back then you had to go Bangkok to enquire and make arrangements for the bike to be inspected at a fee of 27,000 baht if they found the slightest thing wrong you had to pay another 27,000 baht, other cost from memory was 24,000 amin charges and 35,000 registering and getting green book and plate number.