Pretty much
Low Frequency we normally call it 125kHz ( has a range of 30 -300 kHz I think )
So that has a 40bit UID, ( in EM Mode ) so you could use that.
Regardless of mode, you can simply use your UID and a LF Reader ( Or Multi reader ), Equivalent to the KBR1.
Cheap on the usual shopping sites ( Not sure of your preference ), just search 125kHz reader and you should find a wedge type reader, they also do USB form factors.
USB
Or you could use your NExT- xNT with the KBR1, same deal
Depending on sign in security requirements ( Need to change monthly etc )
You could prefix or suffix a pin or passcode that you change.
OR
You could use @anon3825968 suggestion of ROHOS
( That will be another nice commission for @anon3825968 there 
)