Schneider Symmar 5.6/210mm lens neither S nor convertible?

I recently bought a used 5.6/210 symmar online. At first I thought it was a convertible, but it looks quite different from the convertibles I have seen. It does not have the second set of markings (12/370), the barrel is not chrome, but black, and it is mounted in the last version of the compur 1 shutter, rather than in a synchro compur. However, the focal length and aperture markings are on the inside of the barrel (unlike the S version) and it is only marked symmar, not symmar -S. Has anyone had one of these lenses? If so, do they differ in construction from the symmar convertibles or from the symmar -s?