[nytrainer]

Well, you probably mean just by looking at it when it's still in the dash?
Not sure if one can tell if it's a Borg movement that way but I did my 68 clock a couple of years ago (invoice was $60) by buying part from Instrument services here using their kit S-3015. It seems all the sellers sell the same unit so get it wherever.
I've attached 2 pics. With the clock in hand it's easy to see the Borg stamp on the back. I included a pic of the front too as maybe there is a slight visual detail difference if it is not made by Borg (although we're probably just talking about the guts that might be different and not the face).
I took my original one apart first with the idea of cleaning, oiling etc but after some bench testing it was too intermittent and lost 1/2 hour or more per day so I went with the quartz kit. Good luck. Easy to do by the way.