That is a sweet looking 66. It's your scooter, you do what you want.
My 68FLH is rough looking, all original w/the exception of the S&S carb, it even has the original dealer sticker on the rear fender. The paint is cracked and peeling, now and then I'll shoot the bare spots with a can of primer to prevent it from rusting. About a week ago a friend who owns a body shop, offered to repaint my 68 to original HD spec's for cost, alls I hafta do is pay for the paint. I turned the offer down. The way I look at it, to get it repainted would be changeing her soul.
A little FYI, contact HD customer service, tell them you'd like the actual assembly date of your 66.
My 68FLH was assembled June 21, 1967. I've done this to all my old irons.
1968 FLH assembled 6-21-1967
1969 FLH assembled 3-03-1969
1972 FX assembled 8-21-1971