KS;
LW is Long Wave, and that is at frequencies below the AM (MW) band...see:
https://en.wikipedia.org/wiki/Longwave ...there's not much operating on there these days...only radio locating beacons and communications to submarines (and IF you could hear that, it would be a coded cacophony, unintelligible to you or me).
There is still plenty on the AM band, and its often interesting, and from far away after dusk, when the propagation characteristics of the ionosphere change and you can hear stations from 1000miles away!... I always suggest to install the period radio for a vintage look, and have it operational for technical nostalgia, then add modern equipment discretely tucked under dashboard and capable of interfacing with your handheld by way of bluetooth or direct connection.
Adding FM into the radio is certainly possible, but likely prohibitively expensive...when FM was beginning to become more popular in the late '60s, but while people still only had AM radios in their cars, they did produce some FM receiving units which would rebroadcast on AM, so that you could listen to FM through you existing AM radio with these add-ons...of course that was mono only, but if you could find one of those units (which hadn't been recycled yet...actually, I just found a bunch when searching "FM to AM converter" on e-pay), that would give you another inexpensive, certainly vintage option.
Cheers