Many technical universities (especially in German-speaking countries) have institutional subscriptions to standards archives. If you are a student or faculty member, you can often download a DIN 7161 PDF for free through your library portal.
standard, titled "ISO System of Limits and Fits; Selected Fits for Single Purpose Gauges," din 7161 pdf
After conducting a thorough search, I was able to find some information about DIN 7161. Here's a paper summarizing the key points: Selected Fits for Single Purpose Gauges