The pen started out black.
Waterman Nomenclature offers significant challenges, and in particular it is noted that some basic styles of pen had different series numbers (usually based on the "tens" position of a two digit number, eg- the "4" of a model 42) before 1917 vs 1917 and later.
Three eras of model name evolution occur...
1) Pre 1902 or so, each new style of pen (based on shape of pen mostly) was designated by a new number in the tens spot. The original model was single digit model number based on nib size, eg. the Waterman #2, #4, #6 respectively had nibs of #2, #4 and #6 size. As there was (probably) no other structure pen besides the eyedropper fill, straight cap/barrel assembly, this worked well. Once other shaped pens using same name came into play, a number was placed before that nib size. So, the Cone Cap eyedropper such as you seem to decribe here recieved a "1" in the "tens" spot. Note that Cone cap is straight sided, not pointy. Long story. Thus a straight pen with #2 nib was just a #2 (one can think of it as an "02" if he feels need to put something in that tens spot), but the cone cap (cap fatter than pen) with same nib was a #12. If that same #2 nib found its way into a taper cap (a cap that came to a long point at top), that pen now would be a #22.
By early 1900's, had at least those three series of pens, with the final number defined by nib size.
2) the 1902-1916 era got messy, probably leading to the big shift in renaming pens in 1917. During 1902-1916 we saw the introduction of threaded caps (screw caps), safety pens (the nib dials out when the bottom knob is turned) and a variety of self-filling mechanisms.
Instead of making new series by coming up with new numbers in the "tens" spot to add to the tens, twenties and "nothings" pens cited above, Waterman started adding one or another suffix to the end of the tens-series pens. From 1902-1916- using a little #2 nib as our base- the 12-J, 12-S, 12-P, 12-SF, 12-PSF and probably some i'm forgetting, all in addition to the original three series cited above.
3) in 1917 much of this was revamped, especially as some of the pens no longer even were being made.
Most of us see 1917+ pens most often.
Core series post 1916 include (keep X as nib size- a variable)
a) 1-x (tens series) pens- the plain old eyedropper fill, friction fit cap (cap wider than pen, cone cap).

the 0-X pens (the first model Waterman) apparently already had been discontinued
c) the 2-X pens ( the taper cap waterman) apparently already discontinued
d) 4-X (safety pens, previously 1-X-s)
e) 5-X. Probably the most commonly seen series today. Threaded Cap, Lever Filler. Several colors.
f) 7-X. Threaded screw cap (like 5-X pens) but eyedropper fill (like the friction capped 1-X series).
g) 6-X a couple desk pens the fat 67 (which did not have a classic larger #7 nib, but seems to have borrowed name from the late, rule violating "#7 series") and the skinny 62-1/2. Lever fillers.
h) 8-X- apparently a retrospective renaming of the 1-X-P pump filler. Gives me headache. Also used, iirc, for the Waterman Ink View at some point or other.
that's it. I'm fried. Back to work.
david