Why are my tires have a DOT code?

I tire National Command XT in my RAV4. There is no DOT code to tell you what old are they? I know how to read the codes and yes, I'm sure there is no code in these tires. Does this make these tires illegal? Do I some resources (I bought a used car with these tires on it)?

It's on the inside of the tire? I found this on National Highway Traffic Safety ADMINISTRATION Office of Vehicle Safety Compliance tested tires in 2004 if you look at a form in the document and passed their tests www.nhtsa.dot.gov/ Cars / test / compliance / monthly/2004 / statrept.042.doc It wont let me put that together copy everything to your browser

ONE NATIONAL A/S COMMANDO SUV, 245/75/16, TIRE # 30622 $29.95

New Tire 285 70 17 National Commando A/T 70R17 R17 70R $140.00

ONE NICE NATIONAL COMMANDO XT, 225/75/16, TIRE # 30394 $37.95

NORTON Commando DUNLOP Tires Vintage tread 410H19 K81 $245.00

ONE NICE 235/70/16 TIRE COMMANDO NATIONAL A/S 106S 3/32 $28.35

1 New LT 245 75 16 National Commando A/T Tire $109.00

KAISER JEEP CJ JEEPSTER COMMANDO WHITCO TIRE RACK AD $5.75

SPARE TIRE COVER jeep COMMANDO 66-67 73 part auto NEW $20.14

ONE NICE COMMANDO NATIONAL A/S, 245/70/16, TIRE # 28682 $29.95

ONE NICE 245/70/17 TIRE NATIONAL COMMANDO SUV A/S $52.28

ONE NICE 245/70/17 TIRE COMMANDO NATIONAL A/S 110S $58.62

ONE NICE 245/65/17 TIRE COMMANDO NATIONAL A/S SUV $73.92

New Tire 315 75 16 National Commando A/T 75R16 R16 75R $175.00

2 NICE NATIONAL COMMANDO A/S, 225/70/16, TIRES # 28386 $71.95

ONE NICE 235/70/16 TIRE COMMANDO NATIONAL R/S 106S 6/32 $45.08

TIRE COVER jeep COMMANDO part auto NEW 73 67 66 1966 $58.19

New Tire 265 75 16 National Commando AT 75R16 R16 75R P $100.00

1 NATIONAL XT COMMANDO LT 215/85/16 TIRE (F2831) 4-5/32 $15.90

TIRE COVER jeep COMMANDO part auto NEW 73 67 66 1966 $58.19

ONE NICE NATIONAL COMMANDO LTR, 235/70/16, TIRE # 29160 $29.95

245-75-16 National XT Commando tire 2457516 109S OWL $29.99

New Tire 245 75 16 National Commando LTR 75R16 R16 75R $135.00

TIRE COVER jeep COMMANDO part auto NEW 73 67 66 1966 $59.21

2 NICE COMMANDO NATIONAL A/S, 235/65/17, TIRES # 28925 $59.95

ONE NICE 265/70/17 TIRE NATIONAL COMMANDO A/T 115S $40.77

ONE NICE COMMANDO NATIONAL A/S, 245/65/17, TIRE # 27883 $38.95

ONE COMMANDO SUV NATIONAL A/S, 245/65/17, TIRE # 26354 $39.95

1 COMMANDO NATIONAL A/S 245/65/17 TIRE (E1214) 4/32 $21.95

ONE NICE COMMANDO NATIONAL A/S, 235/65/17, TIRE # 22175 $22.95

ONE NATIONAL COMMANDO A/S, 235/70/16, TIRE # 27003 $27.95

Dunlop K81 TT100 4.10 X 19 Norton Commando Tire $119.95

ONE NICE NATIONAL COMMANDO A/S, 245/65/17, TIRE # 24068 $35.95

ONE NATIONAL COMMANDO A/S, 225/70/16, TIRE # 24067 $25.95