welcome
i have the fmf fatty on my streetk5 ,wouldn,t want anythin else ,great pipe!
on my sumo i have a french pipe called Millet ,
this pip had dents everywhere and i repaired them by cutting an opposite window .
then work the dent throught that window and reweld after .
the pipe you have sounds like it is special too ,worth of being restored imo
you can get another pipe and then also fix the burly ,
it will do you no harm ,having a spare pipe
this is my restored millet pipe