How and why do 65 Barracudas have various trunk props?

Both of 65's have the driver side ratchet type prop. One car was built in Sept and the other in Dec 1965. No problem holding the lid in the up position, but there is a problem if one forgets to lift up before closing. A lot of these cars have the hinge mount on the passenger side bent reflecting the oops.
Sometime in early 1966, Chrysler changed to the ill engineered spring type with hook mounts and presto, no more bent hinge mount, but it doesn't keep the trunk lid open either.

My Sept and June build date 66's both have the spring type

I have never seen a factory ratchet style on the drivers side. Not saying not true just have never seen it.