Font from a technical drawing from 1965?

I’m looking for this font used in a technical drawing from 1965, but the source image is so small that it’s hard to get a good match. I have run it through Matcherator, and I think the one that get closest is Myriad Pro (

The numbers, especially ‘9’ and ‘6’ macthes pretty good, and the ‘G’ as well. But both ‘G’ and ‘C’ seems a bit more - how do you say it - closed, in the original. I think I’m on to something here, but any suggestions?

Edit: Yeah, it’s definitely not Myriad Pro, as that’s from 1992… :slight_smile: