I noticed that the oil filler cap on your TR3A is like the cap on mine. My TS number is prefixed with an "8" Mine, a Canadian delivered TR when new bears Comm. No. 8 "TS 27489 LO".
Maybe yours also came into Canada when it was first delivered to North America - in which case your Comm. No. should read "9" TS xxxxx). Is this what you see on the Comm. No. plate ?
Cheers
Don