3B40RT.2000033121.7.bin.gz
3B40RT.2000033121.7R.bin.gz (added 'R' to filename)

##</code><code>##

$fileName =~ /3B4[0|1|2]RT\.\d{10}\.\d+\.bin/)

##</code><code>##

$fileName =~ /3B4[0|1|2]RT\.\d{10}\.\w+\.bin/
$fileName =~ /3B4[0|1|2]RT\.\d{10}\.\{1,}\.bin/
$fileName =~ /3B4[0|1|2]RT\.\d{10}\.\d+R?\.bin/
$fileName =~ /3B4[0|1|2]RT\.\d{10}\.\dR?\.bin/