William Hallett wrote:

Thanks to you both for the dates. It looks as if there is no definite correlation between age and covered vs external shutter bearings.

Very interesting either way... Mine has a later serial number, but earlier lens date, which is interesting. It's too bad the serial number data isn't more conclusive. I guess I'll still keep this as a "very early" feature, though I guess it's not completely clear if these were being produced only before the small cap cameras, or along side them...
They're pretty uncommon either way...I've looked at hundreds of Pacemakers, and mine is the only one I can remember seeing without bearing caps.

Well, to add to your confusion there's an early Pacemaker users' manual posted online at http://www.butkus.org/chinon/ which shows (on p. 11) outside bearings of what I believe you consider to be the "small" style. There's no date on the manual, but it refers to the "All new Pacemaker Graphics", and all the cameras illustrated have Graphic backs, not Graflok, which suggests pre-1950 at least.

and I currently have a 1914-1916 Top Handle Speed Graphic in for servicing that has the small roller bushings covered by the body leather.