Need help ID'ing plug boomerangs --what's correct for 71 SB?

[Mike E.]

Here are three pics of the one side--same issue with the other. Front mount is different on all three. Rear mount is shorter on one than the others. Which is correct, and what are the other two? Thanks in advance for your help!
Thanks!P4300905.JPGP4300902.JPGP4300904.JPG

[Alan S.]

Re: Need help ID'ing plug boomerangs --what's correct for 71 SB?

Hi Mike,
Here's a couple of pictures of the left-side shield from my mid-January 350/270.
Regards,
Alan