Interested primarily in the font for the "4" at the top of the image. This font is found in the 1906 Universal Edition score of Gustav Mahler's Symphony No.3. 

I would ideally like to find a free version of this font (or similar font). The complete PDF of this piece can be found here in case it would help to see more example of the font throughout the score.

Thanks! 

Custom typefaces meant specifically for printing music scores have existed since the metal type days. That's likely what was used to print your sample.

 

Sonata by Adobe is just one digital version of such a typeface that replicates the look of your sample.

 

ITC Clearface Heavy and Durham Abbey are also similar, but not spot-on matches.

 

 

Thanks so much! The ITC Clearface Heavy looks quite similar.

I am a composer and music engraver, so I have a number of the specialty music fonts already that house similar numerals as the original score. Glad to have a full text font now that can match with the numbers! Thanks again!