It’s difficult to tell from your photo whether or not the legs of the R and completely straight or slightly curvy, which would be helpful in determining the precise face used—although it’s also quite possible that the entire display was either silkscreened or hand-painted, in which case the lettering may simply be a stencil-cutter’s/letterer’s fantasy.

Thanks for responding. Indeed, I'm not certain that this particular sample corresponds exactly with any particular production typeface. Nevertheless, I'd be very grateful for any leads on similar production faces—with either curvy or straight-legged Rs.

Close, but no cigar: Gill Sans, Granby and Ludlow Tempo...

Thanks! Ludlow Tempo seems pretty close, especially because the center of the M reaches all the way to the baseline. The only electronic versions that I've found so far are condensed, however.

In the same ballpark, but not quite bold enough...

http://www.myfonts.com/fonts/linotype/spartan/heavy-classified/glyphs.html

but the G in the Extrabold doesn’t cut it...

http://www.flickr.com/photos/depressionpress/6941034037/in/faves-getreal...

Thanks, that's another good option. I'll check my copy of American Metal Typefaces of the Twentieth Century tonight, but I think Ludlow Tempo is going to end up being the closest match. I searched the forums here and it sounds like uncondensed versions of Tempo have yet to make the digital transition. Which is a real pity, in my opinion.

Edit: Here's a shot of Tempo Bold:

It doesn't seem to be an exact match (the S looks a little different, for one thing), but it is awfully close.