I have a 1986 GT hatchback, and my hatch has enough rust that my painter asked me to find a better hatch before he paints it. So far, I’ve bought three hatches, and there’s something wrong with each of them. Are you happy with the Cervini fiberglass hatch? I just checked, and Cervini is out of stock on this item.
Unfortunately I can't give you an opinion on the Cervini's hatch, because I don't own one! My hatches came from Design Concepts (who as far as I can tell is no longer in business) and HO Fibertrends. HO Fibertrends is still in business, but I do not see the hatch listed on their website so they may no longer offer it - but then again, it may be worth the phone call. Unfortunately Fiberglass hatches never really caught on with the average mustang owner so it is possibly that they just aren't made at all anymore. I don't know if Cervini's makes them to order or not...
With that said, I actually found my Design concepts hatch on Craigslist. If you can't buy a new one you may be able to keep your eyes out for something used.
Here are a few pictures of my cars. I never really took pictures to "focus" on the hatch alone, but you will get an idea of fitment.
91 GT - HO Fibertrends
93 LX - Design concepts - This one has a fully finished underside. It is a bit heavier than the HO, but not significant for a street car. It is more similar to the Cervini's part as far as I can tell. As an aside, there was a rumor long ago that Design Concepts were cast off Cervini's parts that weren't up to Cervini's standards. I could never verify that, though.
Car is a WIP but they are the best pics I have at the moment.
Anyway, I didn't really want to hijack the thread, but I guess the takeaway is that Fiberglass parts can look okay if they are finished correctly and care is taken to get them to fit right. Also, I don't own Cervini's hatch, but the ground effects and rear bumper on this car are Cervini's products and I was happy with their fitment.