Will flashing a custom ROM relock me with SIM carrier?

I got a Samsung Galaxy S5 (SM-G900P, Sprint) running stock Android 6.0.1. As it comes, it's a CDMA phone, but I got it unlocked at a phone repair shop to use GSM and it has been working fine, but it only goes up to 3G. If I flash a custom ROM (lineage-14.1-20171004-nightly-kltespr-signed), will my unlocked phone stop working with the SIM? or the unlock will remain after the installation? P.d: I don't know if it's relevant, but I'm outside the US.