The ID plate should be an ADR type plate and should be fixed to the body on the bulkhead immediately behind the brake booster.
It only shows CAR number ie YG2S4 plus CAR number and the month and year of manufacture. There should be further info on the radiator surround panel. This should show the BODY number and an internal production code possibly M 06 but not 100% certain on the code for a MK2. The BODY number should be approx 500 less than the car number.
If CAR No is YG2S4 1234 then body number would be 734 (1234-500).
BMC numbering starts at 0001 for the BODY number and 501 for the CAR number. Why???? Just another one of those BMC mysteries.
There is no mention of engine numbers.
If I remember correctly the paint type and colour, code etc should be on a stick on label attached somewhere on the RH front part of the car maybe on the bonnet latch panel. The paint type shows what should be used to refinish (ie repair) the paint. Original paint would most likely be baked enamel.
MK 1's and earlier cars prior to 1969 manufacture had the BMC type plate with a bit more info (but no build date) attached to the bulkhead behind the master cylinders.
Hope this helps
RonR