Digging around again and found this piece. Chrome is very nice.
The part # is 7724813. It is in fair shape but is missing 4 of the 8 studs. Both end studs are intact.
Over all length is app 60 1/4" Correct for convertible. $75 plus the ride.

 

Still available.

 

Bump. $60 +ship.

 

$50 + ship.

 

Question- what did these look like brand new? was there a gray paint background? Yours looks about in the same shape as mine.

 

Boese, Though I have never seen a 68 survivor I believe it was sliver gray, possibly argent maybe?
How I do it is to clean it real good (yes the trim piece!). Then spray it with rattle can chrome (Krylon). Gently wipe the high spots with a lacquer thinner dampened (not wet) lint free clean wipe to bring the chrome back out on the high spots. After its good and dry I put it on the car and go. Takes some patience and a steady hand. The rattle can paint has enough contrast against the chrome that it looks good to me. As this ages it gets even better as the paint flattens out. The trunk trim on the red car was done back in 90. It still looks show room. Another note is if you dont get it right just wipe it down with thinner and spray again till your happy.

 

I've seen a couple original pieces (I had a parts car that the trim was removed from in 76) and I tried a few times to duplicate it and I can't ever get a good match to the original. It's a very light silver gray. You can almost see the chrome underneath. Then you take the paint off the high spots as described by droldsmorland.