I'm in the same case. I have a Tek 1765, I removed the Nvram Dallas DS1225 for to backup the calibration, but when I read the memory, the memory was empty. In the threads about oscilloscope Tek 2465 talks about what happened me, a operational backup memory that is ereased when you remove and try to read it.
I see a link for download the Tek 17xx calibration software but it don't work.
https://www.tek.com/en/support/faqs/where-can-i-get-1740a-1750a-or-1760-calibration-softwareService manual in page 2-13 talks about a program for to download the calibration data to a PC, nvsave.exe, and for upload, nvrestore.exe. That programs are ideals for to download calibration data for to replace the Dallas nvram DS1225.