Historically, I can tell you that the first burgundy I ever saw was a beautiful 4001 in the dealer's shop in New Orleans, LA, in late 1970. It was displayed under a very bright spotlight in the store window on Canal Street, just outside the French Quarter, next to a 1970 FireGlo. It was a truly drop-dead beautiful guitar! By comparison, side-by-side, that burgundy 4001 made the fireglo next to it look almost like something Fender painted.
Came back the next day with money, every dime that I had been saving up to airbrush my 1969 Dodge van, but the bass had been sold! Went in to ask, and the dealer said he could get another one. Waited until late March 1971 to get the call back, and he had a March 1971 21-fretter 4001 in Burgundy with serial number KC012. Bought it that day, $285 with a HSC (man, those were the days!) and had it until Sept 1986 when it was stolen in a burglary. I really, really miss that bass...
It was finished a VERY dark burgundy, meaning that the bass looked black - like an eggplant - unless extremely bright sunlight or a stage pinbeam spot was on it. You could hardly tell it had walnut wings, it was so dark.
All the early ones I ever saw were this shade. Dale was working at Rickenbacker starting in 1972 I believe, so he can tell you if he ever saw one in 1972 or 1973 that was any lighter. It was not spray-booth inconsistency I don't think, because I remember seeing dozens of them over a four year period, all the same dark eggplant shade. Later, in and after 1974, I stared seeing guitars coming from the factory to dealers with ever-lighter burgundy finishes, until by the late 1970s you could see burgundy showing up as almost a candy apple red (but without the metallic undercoat that you see in ruby).
I actually bought this past November a gorgeous original-finish May 1973 burgundy 4001 from Jon Casselman, and the photos he sent me before shipping it showed that it was exactly the same eggplant-dark burgundy of my dearly-departed March 1971 4001 bass.
I wish I could show you recent photos of it under bright light, but frickin' UPS lost it in shipment

I never even got to see it in-person
Just this past month I also bought a February 1968 4001, an April 1971 4001, a March 1972 4001, and a July 1973 4001. At least one of these, and maybe more, will be refinished in eggplant burgundy (probably the 1973 - it is a jetglo that needs some major finish work to start with!), and it will be the same exact shade of burgundy that was on my beloved March 1971 21-fret 4001
You will be able to see it when it is finished, I am sure, either on Dale's new web site that we are developing for him at
http://www.dalefortune.com or else Paul's new web site (if Dale gets busy and can't do the refinish) at
http://www.jingle-jangle.us, or maybe Ted's new web site at
http://www.staberow.com if both guys are too busy
BTW, don't tell Dale!!

The web site is gonna be a surprise present, once we get some content up about him and photos of some of his projects that he has posted here on the Forum in the past!