It may depend on the age of the tool William. It is often hard to tell what the original colour for an 'older' machine may have been as early machinery catalogues were usually printed in B&W and older machines have often been repainted at least once over the years.
This is a small watchmakers lathe and it may well have been (re)painted by someone. I'm not really sure that Lorch would have used a metallic paint originally either. For something this size, I might be tempted to clean it down to bare metal and polish/buff it. Alternatively, why not choose a colour that you like and at least make it look presentable.
The later Lorch Instrument lathes (a wee bit larger than yours) seemed to have been painted a light green and that could be a good choice for you. I have a very old (and much larger) Lorch Schmidt AB (pre-WW1 probably) that was in very poor condition when I first acquired it. I decided to paint it black, simply because that seemed to suit the machine and it needed a lot of cleaning up. It also required as much on-going protection from the damp in my workshop as possible. Your small machine will presumably be kept in much nicer conditions indoors, so your requirements are likely to be more cosmetic.
Regards,
IanT