Very interesting ! I assume you mean frame, not engine number.
From my ownership of a 1913 machine, you need to look at the front of the headstock for the frame number, low down, about one inch up from the bottom bearing.
You may be looking for 4 digits, which face forwards, in a horizontal pattern thus :- X XXX, where the first digit is the factory number of the frame builder who made the frame and the other three digits are the actual frame number. With these three digits, it is easy to date the frame, according to the late John Underhill (past SOC Machine Registrar), who must take the credit for most of this information; if you find them, let me know.
Regarding the radiator, up to early 1915 the radiator was 4 bolt mounted, but with SQUARE honeycomb, not like yours, so the 4 bolt mounting on yours could be irrelevant, especially as the core does not have an inlet pipe – hence the two non-standard inlets into the header tank.
Does your frame have lugs for 4 bolts?
After early 1915, the radiator was 3 bolt, with a frame to match.
Regarding the oil filler, the 1912 Scott sales catalogue picture was the last year showing an oil filler behind the handlebars; in 1913, the oil filler was under the “nose” of the saddle.
Incidentally, thank you for your comprehensive profile – I really don’t like dealing with informationless nom de plumes!