EFI vs vtoc

Dear All,
I've formatted a disk with dd command in 2 different disks [146GB and 72GB], the first one it took an EFI label, the second one took vtoc label, is it strange? why the first disk is formatted EFI instead of vtoc, here is the prtvtoc of the 2 disks:
===
 prtvtoc -s /dev/dsk/c4t5000CCA00072AB3Cd0s0
*                          First     Sector    Last
* Partition  Tag  Flags    Sector     Count    Sector  Mount Directory
       0      4    00         34  33554432  33554465
       8     11    00  143358321     16384 143374704
===
prtvtoc -s /dev/dsk/c4t5000C5000F3DB49Fd0s0
*                          First     Sector    Last
* Partition  Tag  Flags    Sector     Count    Sector  Mount Directory
       0      2    00          0  33560448  33560447
       2      5    00          0 286698624 286698623
===

Br,
Chafik