Adding rear seatbelts vs. collectability
 

Pelicans, yes another question
My 67 targa has no rr seat belts, part of having this car is to spend time with my boys and infect them with this this hobby and the greatest mark in car-dom. I have seen 60's with rr belts, were these an option or an add-on. I can fab a replica that will be indistinguishable from the original. But will this affect its value? This is a petty question I know but I am curious.
Thanks for your input.

P.S. this car is visually original with mods limited to ER suspension upgrades and
some of Henry Schmitt's magic in the planning stage.

I can't answer your value query.

I am guessing you are talking about adding lap belts, not 3-point belts. If so, you may want to look for accident studies on lap only belts. There have been some pretty horrific injuries caused by these.

If you take your kids for rides a lot, I would install seat belts. You can always remove them later and patch over the holes. Any seatbelt (even lapbelts) is better than no seatbelt. 75% of people ejected from cars in accidents die from their injuries.

I added peparts.com rear seat belts to my 72. The threaded holes were already there, and I just saved the plugs if I ever want to reinstall.