Just bought a Topcon 313 in perfect shape. I am trying to look up the serial number for this instrument to see when it was manufactured. I have scoured the TOPCON website with no luck. Anybody have any ideas?
You might try talking to Pete at optical engineering. They are out of Marietta . He's been selling topcon for years, and might know which numbers mean what.
I bought a GTS-303 in 1990 or 1991. The 311, 312,and 313 came out about a year later. Still use mine sometimes.
Check out the Topcon Museum. It is helpful in determining the vintage of older instruments. The 310 Series is listed as having been introduced in "1997".
http://www.topcon.co.jp/en/positioning/museum/ts.html
Also, the GTS-310 series instruction manual is available, although at quick look, it appears to be un-dated. One of my elementary school teachers insisted that I always put my name and date on any paper I submit. It was only later that I learned to add a north arrow.
Finally, there was a feature called Google timeline which would sort results based upon when they were created. Although the internet may have been in its infancy when the 310 series came out, I'd say you might figure something out using that tool...
Good luck.