I am trying to get an idea of an age of Manhattan Optical no.2 Verastigmat lens. There is very little info out there for this lens other than it being a 4+4 anastigmat. I know it's no later than 1902, as it's stamped Cresshill.

I was thinking I might get a better idea from the serial number relative to serial numbers of some other Manhattan Optical / Gundlach lenses that there might be more information about. I stumbled on this piece on a Gundlach shutter, that reckons it's prior to 1893, the lens there has a serial number of 5743, with the writer speculating the serials only started at 5000. My lens has a serial of 5161, so that would make it bit older, but that's making lot of assumptions. With a few more serial numbers it should be possible to get an idea if that might be the case or not if you have a Manhattan Optical / Gundlach lens, and would not mind sharing the serial, I'd appreciate that.