I don't do as many as I used to, but to make a few extra bucks, I will buy, rebuild, repaint, and re-sell implements and tractors. I'll do them in the wintertime more often than not. I like to paint them as close to OEM as possible, even decal them as accurately as I can.
The best source for accurate paint detail and decal locations is old sales brochures. I've always been able to find something of use on EBAY. Usually they'll run anywhere from a couple bucks to $10 or $15 for implement sales literature. New Holland parts manuals for individual implements will have decal locations and paint color codes, but they aren't very helpfull with the actual paint scheme.
Another source is old farm periodicals. Prarie Farmer, Successful Farming, ect.... Lots of adds. New Holland advertised heavily over the years. Pictures of the #55 rake should be reasonably easy to find in magazines. They're usually available at bigger antique farm shows, flea markets, swap meets, ect.