NIKKOR FOR BRONICA

I am trying to find the date of manufacture for a 75mm 2.8 NIKKOR on my S2A. The serial number is 178306.Thanks in advance for any information

This source indicates the lens should be post-1971

http://www.photosynthesis.co.nz/nikon/serialno.html#Bronica

Perhaps not multi-coated, since according to the same source, multicoating appeared somewhere after S.No. 250000. Should be a five element in four groups kind of lens, although I don't seem to find a lens scheme, maybe someone else can help with that.