N167 Dating
 

I was re-reading parts of the Old Judge book this weekend and it got me thinking. I think the evidence suggesting that production of N172 started in late 1886 is pretty convincing. That being the case, I wonder if it is possible that N167, the predecessor to the mammoth N172 set did not come out a year earlier, in 1885, rather than early 1886 as has been the conventional wisdom. Are there hard reasons to suggest it is not an 1885 issue?
Thanks,
JimB