Ail TRs from TR2 to TR4A were fitted with 4J x 15 wheels (unless wires or some other option were specified, of course). 

The First Edition TR2 Parts catalogue shows that steel disc wheel as 301672.  Later sidescreen car editions of the parts catalogue show that from TS13046 onwards it became 302262 and that remained the only part number for standard steel disc wheels right to the end of TR4A production.

 

The change of part number from the early 301672 to 302262 did not change the width - the width remained at 4J,  but it changed the inner offset very slightly.  Later 4J wheels have the rivets for the wheel centres about 3/8 inch (0.375) further towards the outside of the rim.

 

308288 was the disc wheel introduced for TR5. This wheel is  4.5J.