Im building Tamiya's and want to put it in the of the 4th Armored Div marking but it seems tamiya must have left something out
all thats there is a black star fr the turret side and a white star for the hull side no bumper codes or serial numbers was that normal or did Tamiya forgot those?

The answer is complicated. Serial numbers might get painted over with camo, or if the tank was resprayed, and appear not to have been re-applied afterwards - they may have been seen to have served their purpose once the tank was issued. Bumper codes were added with temporary paint (removable with gasoline on a rag) because they changed if the unit was reassigned, and were sometimes removed for security reasons (to obscure unit deployment info from the enemy) and were placed in areas that quickly got covered in road dust and mud, so even if they were there they might not be visible in photos. (Same goes for serials - front-on pics make the rear side of a tank hard to see, and stowage hides a lot.). Kit decals often work on what can be seen in one or two readily-available pics so obscured markings get left out. Unless I have photos to prove otherwise I just assume the missing items are hidden, and detail my build accordingly.

Operational security. Often serial numbers and bumper codes would be obscured. Serial numbers can be used to count tanks, even figure out units and production runs just like researchers and historians do now. So they could be scrubbed off the side of the tank.

And often there just wasn't time to put unit markings on replacement tanks pulled from the motor pool.

Read Spearhead A special event photo op and suddenly unit codes and the serial number would be freshly painted on the tank.