colrehogan wrote:

Assuming that the QT serial numbers that I see there are supposed to be QR...

​There were QT and QR prefixes. QR models are a post 1952 prefix and have the same numbering sequence as QT models.

Dick, the Typewriter Database is a great site - you can lose hours on it... 

A few points:
1. Identical numbering ("same sequence") means a QR number would be the same as those with a QT prefix.

2. I would caution you not to use the manufacture years quoted in other people's galleries. Some people don't look up the numbers correctly, others just don't have a clue as to what they're doing, and consequently the wrong year can be entered. Another scenario, which has happened to me several times, is when newly uncovered information modifies an existing serial number list. For example, when you create a gallery and state that your machine was manufactured in 1956 based on the information available at the time, you might find later on that an update to the serial number list now states the correct year as being 1955. I rarely check these things with my own galleries (who knows how many of them have date errors right now), but I have found a few that had the wrong year because of updated serial number lists. Supporting this, I know that the Remington serial numbers were massively overhauled not all that long ago, so galleries that were created prior to that update could display inaccurate information.

3. Remington models were produced in several different countries and some used unique prefixes and numbers, and some didn't. In some cases this is well know and noted in the database, and in other cases it's a great chasms of missing data.   
4. The Database presents information that can vary from being deadly accurate to a best guess. Keep this in mind when using it. It is a valuable reference tool, and not a final word. This holds for other aspects of a typewriter too such as model names. Be especially cautious of the comments made in galleries; too many people read pure speculation as if it was a fast fact.

5. If in doubt, or if it will help you sleep better at night, I'd suggest putting a "c." in front of any year you attach to your machine... 
 

At last, I can rest easy knowing someone else has as bad a sense of humor as I.

~Joe