I have remembered make and model of vehicles that hit me in a car accident even though i was knocked out during the incident ... sorry that above sounds like hogwash.
You know about makes of vehicles because A) you've seen them on the road, and B) you've seen pictures of them on TV and the internet. Neither of those apply to monsters in my campaigns, where:
A) Most people have rarely if ever seen a monster. And those only the most common. PCs begin as neophytes, and only know what they've seen with their own eyes, or heard garbled campfire stories about. Until a PC encounters one face-to-face, a roper, gargoyle, or behir is a rumoured horror, not an object of scientific study.
B) There are no illustrated encyclopedias of monsters for scholars to research. If there's any information at all, it's sketchy second-hand accounts from unsavoury scoundrels and boasting treasure-hunters.
How many makes of cars would you know by sight if you've only ever heard verbal descriptions of them from unreliable sources?
For a historical analogue of how a pre-Enlightenment medieval society regards monsters, look at 15th century drawings of sea creatures. Even the educated people of the era imagined all sorts of fantastical and garbled nonsense. The depths of the seas and jungles were terrifying and unknown. So are the wilderness, ruins, and dungeons of my D&D worlds.
I'm not saying anybody else is doing it wrong. This is all just a matter of personal preference. I put a high premium on mystery, strangeness, and immersion.