Mamiya Sekor 250mm f4.5

Does the Mamiya Sekor 250mm f4.5 lens (RB) come in a "C" version? IF not, is the regular version acceptable for use?

Thank you

Michael

[sarcasm]Only ignorant fools who work to unacceptably low standards use Mamiya products. Professional photographers have used RB67s and lenses to fit them since they were brought to market. Professional photographers are ignorant fools who work to unacceptably low standards.[/sarcasm]

According to these site, the answer is: yes the 250/4.5 came in a "C" variant.

http://rb67.helluin.org/lenses/