Help please - Anyone familiar with G&L truss rod nuts

[Shylock]

I have just bought a rather nice G&L CLF Research L1000 2018 and the truss rod nut appears to be missing. The person I bought it from was the original owner and, having just messaged him, he thinks it has always been missing and he has never adjusted the truss rod. 

I attach a picture and all appears there is the thread. It is a dual action truss rod and there is comment on the internet that there should be an integrated bullet that is welded on? 
 

Can any one help or point me in the right direction- thanks 

[Mudpup]

A few years ago i had a USA L2000 that had a rounded off truss rod nut. I think it was a 4mm allen key one. The Bass Gallery repaired it easily without removing the rod and i seem to remember they welded a new one on

[3below]

Dual action rod should have the bullet welded on, earlier G&L basses have a removable truss rod nut and mixed reviews. I would take it to a luthier who knows what they are doing.  I have two USA G&L basses - one since 1990, totally solid, the other (circa 2006) decided that the trussrod needed to make a break for freedom.   You have the bonus of a rosewood fretboard, if a trussrod replacement is needed it is do-able.

[neepheid]

Yeah, sorry mate, that doesn't look right - this is my 2020 CLF L-1000...

 

 

4mm hex iirc.