alrighty, ill answer your question in the simplest possible way,... then close it,, please refrain from making another thread too, this information is in the stickys as well
create a new folder on your desktop, name it whatever you want
put a copy of the 1.2 goku in there
in milkshape go to "Tools>Half Life>Decompile Normal HL MDL File"
a box with 4 selections will pop up, leave all the boxes selected and click ok
create another folder on the desktop
put the goku model you are trying to add the skeleton to into it
in milkshape go to "Tools>Half Life>Decompile Normal HL MDL File" again
UNcheck sequences and qc file you wont be needing those
now drag those files created from the goku you want to fix into the folder of the 1.2 goku
if it asks to overwrite hit yes,
now in milkshape go to "Tools>Hlaf Life>Compile QC File"
if everything was done properly the MDL file of the 1.2 goku in the folder on your desktop will have been changed into that of the goku you were trying to fix, but with 1.2's animations
you may have to rename the reference smd of the ssj3 goku to make it work, i dont know if they have the same name or not but they should,