In my case, the tach was squirrelled away long ago, so unlikely it has a replica dial. The insides look like they haven’t seen the light of day since before WW2. It seems odd to me that there are no numbers on the dial, although from what I understand they can be a little cryptic at times anyway. Assuming I know what I’m looking for, it doesn’t have an idler gear on the drive, so it’s not a CCW unit. Again, it’s an assumption, because I know nothing about chronometric instruments. I suppose if I figured out the ratio, that might narrow down what it came off. The history is unknown... it arrived along with Vincent, and Norton OHC bits, but that doesn’t necessarily mean it was from a Norton.