Ubi also added the Hours of Darkness OST soundtrack to YT
Unfortunately I couldn't get the link to work right. Dunno if it's local problem with my ISP, but spotify also has the soundtrack if you are having problems with the YT one as well:
NOTE: this is just the instrumental music they designed for the DLC. I have NO idea what songs (if any) we will get over radios. With it being Vietnam war one would hope you get some rockin' soundtracks like stuff by CCR or the Stones, but maybe we won't. Interestingly there are some file entries for Hanoi Hannah (https://en.wikipedia.org/wiki/Hanoi_Hannah) who was a notorious Vietnamese radio personality trying to make Americans feel homesick (psychological warfare at it's finest). It's possible we may get "news" and propaganda from her over the radio.