Duster trunk seal

I replaced the trunk seal in my 76 duster with a D-shaped seal from metro. Part # is TK 56-B/18. Now of course, the trunk will not close. I have seen posts about using a different shaped seal to correct this problem. Is this the only solution ? I have my original seal and it is D-shaped. Has anyone been able to make a D-shaped seal work on a duster ?
Thanks for any help !