TR3
1955 (Oct)
TS 8637 1 3/4" Stud Mounted Type H6 Carbs, Grille Flush w/Front Apron
TS8997E: Change Manifold Inlet; Added Cam Bearings
TS 9350 E Change Manifold Inlet, Head Gasket
TS 9731 E Changed to Stiffer Pistons
1956 TS 9666
TS 9952 Change in Filter Head (Oil)
TS 11384 Added Second Silencer to Tailpipe
TS 11716 Change to Headpipe Clamp/Bracket
TS 12567 Changed Windscreen Wiper Motor Type and Location
TS 12606 E Changed to High Port Cylinder Head Assembly
TS 12650 E Change to "Flow through" Filter Head
TS 13046 Changed from Lockhead to Girling Braking System, Changed Master Cylinder,
Front Disc Brakes, Rear Brakes, Rear Axle, Differential, Suspension
TS 13046 Changed to large "T" Pedal Pad
TS 13052 E Change Manifold Inlet, Cylinder Head Studs
TS 14823 Changed Rear Axle Cover
1957 TS 15014
TS 15334 Changed Wheel Cylinder Assembly
TS 15497 Changed to Flexible Fuel Pipe, Petrol Tap
TS 15706 Changed to Combined Tail Pipe/Silencer
TS 18230 E Changed to Chromium-Plated Rocker Cover, Changed Oil Filler/Breather
TS 18902 Change in Oil Drain Plug
1957 (Aug) TS 22013 LAST TR3
on the link at VTR TS13046 is where that change happened so just check the production number...
https://www.vintagetriumphregister.org/TR2/TR2-production.shtml
Good luck