Yep, you did get lucky and it should be fairly easy to replace once you get it home since you already have the holes in the right places.
I have the ready brake system but no longer use the brake cable. When I switched toads a couple of years ago I couldn't get through the firewall in the right place so I switched over a Patriot system using the same tow bar.(I also let the sensor light go with the MH when sold:S).I will still use the Patriot system in my new toad.
I never saw any wear on my cable and still have it (somewhere) after several years of towing. It is a great system and yours is the first problem that I've heard with it.
Chris
2008 Holiday Rambler Scepter 42 PDQ
2018 Ford Edge SEL- Ready Brute Elite Tow Bar/Blue Ox Base plate/Patriot Brake System
Retired Canadian Army WO (1971-2000)