Most of the subway system today has been updated in the past year or two years--station signs are always replaced, strip maps get new stickers, and the MTA keeps things current. In the cars themselves, SMSs have replaced floors and painted seats, while various stickers have been replaced in past years for fleet uniformity. Almost every car in the fleet has post-1987 graphics on the interior, which tend to be white on black stickers in the Helvetica font. Not to mention, everything is in English.
In the 1970s and 1980s, however, signage looked a lot different. The common font was Akzidenz-Grotesk, the signs were black on white, and Spanish was used for a lot of the text around the cars. Almost all examples of this design language have been scrubbed from the system either in routine updates or GOHs (the oldest R32s and R42s actually have relatively modern interior signs thanks to their overhauls). But a few cars keep the original 1970s-1980s graphics, and these are the unmodified R62/As and R68s (68As came too late).
I try to catch a photo (on my phone or camera) of the cars I see that have kept their original stickers, as they're a nice throwback to a time when the whole system looked like this.
Starting with R62As, these English-Spanish Azkidenz-Grotesk "Do not use this door" stickers are still around on a few cars, namely the 42nd Street shuttle fleet.
The rarest of all are these "Prohibited" stickers, which are only on a handful of R62As at best. At one point in the 1980s, this was the sticker on the storm door of each car, whether R30 or R62. The font is pretty unique.
While talking R62As, a bunch of cars have retained their original number stickers, which are black on a clear background in the Azkidenz-Grotesk font. Here's 1907:
Closer up, here's 1787. This car also has its original Emergency Brake sticker in English and Spanish.
A few cars also have these original New York City Transit Authority stickers for priority seating, which have stuck
around on buses but not subways. These are in Azkidenz-Grotesk.
A few R68s also came with these stickers, but theirs are on a white background. I've only seen them in Helvetica, but the M logo is a nice throwback.
R68s and R62/As also came standard with these "Prohibited" stickers, which I've only seen remaining on R68s. They are in Azkidenz-Grotesk on white, while their bus counterparts are Helvetica.
R68s have also kept many of their original number stickers, which are either in Azkidenz-Grotesk or Helvetica in black on white. Next to these numbers are storm door stickers, which are also in either font.
A-G numbers and Helvetica sticker:
Helvetica numbers and an A-G sticker:
Helvetica closeup:
Akzidenz-Grotesk closeup:
One last piece of 1980s-styling which is more physical than graphic is flooring. A handful of R62As have kept their original beige flooring, like 1958:
And finally, one sign that's older than a bunch of these put together:
The details are easy to miss, but there's a lot of history hidden around the cars and the system.