2 ways 2 go about it. Cut and use the original fittings on the new lines. Or take the fittings to an older parts store, find an older guy and tell'm you need to adapt the new line fttgs to the old ones.
This just occurred to me - aren't "modern" brake line fittings metric?
Kinda off the subject. On cars-n-trucks, yes. No stores round here that carry metric w/bubble flares. Have to buy standard tubing w/inverted flares and standard to metric adapters.