My 1894 CEO SN starts with a P, i believe the 1900's start with a Q. I also have the red front sight on mine but i believe researcher told me that it wa not an available on 1905 guns from the factory, but they may have been using them on the 1900's, Researcher said it is called a Bradley front sight.

maybe post here, you may get your answers:
Remington Society of America

here are pics of mine:
http://www.remingtonsociety.com/forums/viewtopic.php?f=7&t=4946