@ahelper: Yes, for instance I recently got a '68 MW300T from a fellow hunter, serial #K8179939. if I go here:
https://typewriterdatabase.com/typewriters.php
I can use the search box just above the list and type in K8179939, and behold, you see the machine entered twice, once in my collection, and once as a sighting for the previous owner. If anyone else had entered it also, they would show up as well.

It's important to note that the search box only searches the result list you have currently up, so typing that serial on this list:
https://typewriterdatabase.com/typewriters.php?mfr_search=72&model_search=Quiet+De+Luxe
none would show because there are no Royal QDLs with that serial number.

Regarding the numbers of portables vs. standards, it's important to note that while standards very much outsold portables (until sometime in the 70's, I think), standards were business machines that got used up and often scrapped at the end of useful life, while portables are often rarely used and kept in cases that are usually kept inside. Additionally, I was curious about the discrepancy years ago and asked a few typewriter dealers about it, and was told that in the late 80's/early 90's, there were guys that drove around to typewriter shops, bought up unwanted, usable standard machines for scrap prices and drove them to Mexico to sell to businesses there that still wanted them. So a whole lot of them got shipped south and probably used up & scrapped there. For me, that tracks with what I saw in the printing business around the same time as digital copiers started supplanting small offset printing presses. Those got bought up to be shipped to countries that still had good use for them.