Hi Rob,
Question #2. You can get an entire Optikleen Washer Bottle Kit from Original Parts Group.
www.opgi.com It includes the bottle, lid, label and stainless steel bracket for around $50. Loren, I did not know that it should be green fluid. Here's a photo of mine with blue fluid.
Question #3. Here's what I have so far for your particular codes...
First group
W = Tinted windshield only
Second group
L = 4-speed transmission
P = not sure at this time, may be clock
Third group
You have none of these options. H = wide beltline trim at side windows, B = rear window defogger
Fourth group
S = not sure at this time, might be some trim code
Fifth group
W = Custom seat belts with retractors
Regarding the "P" code in the second Group, it has been suggested that it could be Push Button Radio, Rear Speaker, Clock or Back up lights. I am leaning towards Clock for these reasons. My convertible does not have a "P" code, however, it does have a Push Button Radio and Back up Lights. Most '65 GS came with these two options. When I was the Record Keeper of the '65 GS Registry, I went through all the information from submitted trim tags and compared with options listed. There was a pattern that if they had a clock, they also had the "P" code. Rob, does your GS have a factory clock? There was not enough data to eliminate a rear speaker as a possibility.
I would like to review these records again, but Chris has all the Registry documents now. Chris, feel like spending a weekend doing research?
Rob, you and Mark need to get together. Mark's work can be an inspiration to help you stay on target with your restoration. Good luck.
John Egel