['ol Pinion head]

When it comes to reproduction sheet metal panels, there are only so many actual manufacturers. I've been told only two in Taiwan, and those family owned business names are not recognizeable.
That's straight from a supplier that made the trip overseas & walked though the manufacturing facilities. To assume multiple different die stampings of the same large complex part, no that is not what we've seen.
I put this out there as a response to those that really think there are multiple companies investing a lot of funds to stamp out their own version of a relatively low volume expensive reproduction panel.
That's a total different deal with small items like partial floorpans & cheap 3 piece trunk pan repair panels.

For the '70-73 Firebird full quarter panels , trunk drops, inner & outer tail panel, Ron Johnson (National Pontiac vendor, collector. & PY member) worked years ago with the Goodmark entity to proof & make sure these panels fit well.
Goodmark also marketed numerous other pieces that fit well.. many times not perfectly as original, but often small issues noted upon installation. In the Pontiac lines, the "68-70" GTO hood, the '70 GTO fenders,
'70 GTO core support (that needed removal & reconfiguring of the lower rail). Goodmark pieces are still out there, but the product line was sold to AMD a few years ago.

DynaCorn... DII... lot of product out there, many pieces 've personally examined as well as in the hands multitude of very skilled metal/body workers.
For specific Pontiac usage repro sheet metal, have not been very impressed.

AMD... lot of Chevy & Mopar offerings. Several other product lines run off dies prev producing Goodmark labeled content.

Golden Star...have had limited experience with pieces coming from this entitiy. Since Goodmark is no more, seem to see a lot more product labeled Golden Star....just a thing that makes one go hmmm?
A few years ago, a local customer picked up a Golden Star branded "69-70" A-body 3 piece trunk floor set, & I was less than impressed with it.

Disaster repro Pontiac sheet metal product of the year...
Late last summer examined a pair of reproduction '66-67 LeMans/GTO doors. Totally missed the target, waaaay too short length wise.
3/4" too short on the bottom edge. 9/16': too short at a parallel line up at the door handle mounting point. I compared to three nice original '67 GTO doors, and took pictures
of original '67 GTO lower door stainless molding sticking out in the air when properly lined up on each side door.

Unfortunately, there are body shops out there with owners or managers who take on jobs requiring major panel replacement, then the biz owner or customers order these "new" large parts instead of sourcing nice used.
Last, instead of raising H#LL & sending the ill fitting junk back, they accept the garbage & set one or two of their employees off on a mission to "make it work". The clock is ticking...
It's amazing, but I will never understand throwing 150- 250K in "build" expense into such disasters.