The countries still using the OIRT FM band are Russia, Lithuania, Belarus, Moldova, Ukraine, Turkmenistan, Tajikistan, and Kyrgyzstan. All those countries also use the more familiar CCIR FM band.
An old "TV Sound" radio with continuous tuning should have no trouble picking up signals in the OIRT band, if you are in an area with such stations.
If you search You Tube for "OIRT bandscan", "OIRT radio" and "OIRT Moscow" you'll find many audio samples of stations in that band.
There are a few modern portable radios that tune the OIRT, Japanese, and CCIR FM bands. There are also a few technical geeks who have modified CCIR receivers for OIRT reception.
I have read that some of the OIRT stations use different subcarrier frequencies to generate a stereo signal (31.5 kHz instead of 38 kHz) but those would still work in mono.