Road Runner History and Identification

Can anyone supply info about, or offer reference sources for, the following?

What is the date of the first Road Runner production vehicles to roll of the line?

Is there a record of quantity of the 1968 production, by both month and assembly plant?

Is it a different start date for each of the 3 assembly plants (Lynch, St. Louis, LA) or did they all start simultaneously?

On the fender tag what does the shipping order number signify? (the tag in question is a 1968 Road Runner, SO# 900505, what does 900505 mean?)

On the fender tag are the codes Y9 (special order) and 999 (special paint). Unfortunately, there is no broadcast sheet. Is there anyway to know the dealer for the Y9 (can’t locate previous owners) and anyway to know the original paint (besides the physical inspection)?

Thank you for any assistance, Dan.