Exactly. With a taking lens, the issue is one of the lubricant slowing down the action of the iris as an exposure is made. The presence of a viscous material retards the smooth and unimpeded action of both iris and shutter blades. With the enlarging lens, this is not an issue.
I am in agreement with Doug on this one. Clean off with a little lighter fluid any lubricant on the exterior that is easy to get to without dissasembling the lens. Oils can volitize over time, but unless this becomes an issue and fogs the lens elements, not to worry. A second on the Acetone. Too many lenses use plastic parts inside, or even the barrel of the lens. Acetone can render them Dali-like gooey messes.