need help with a rear override bar

hi,

I have a 71 datsun 240z with a build date of 7/70.

Can anyone tell me if their are two types of override bars for the rear bumper. I purchased one on ebay but it will not fit my bumper. The car had one installed by the dealer but the last owner sent it out to be recromed and never received it back. The one i bought on ebay won't fit because the mounting wholes on the bars wholes by the licence plates have a center spacing of 10 3/4 and my bumper has a spacing of 9 3/8 can anyone help?

thanks

looking for a z