That's an old battery number. If you go to Walmart by their watch counter you will find a bunch of batteries and on each package it will tell you what battery number they replace. I believe the 2032 replaces the 3032 and that they are interchangeable.
The MOST COMMON are computer motherboards, they been putting them on those for over 20 years, now think how many computers have been built since the mid 80's.......keyless remotes have been around only a few years so not the most common use. I agree Wal-mart is the cheapest place to get them a couple of $$