The "Professional" cue is two piece. I had toyed with the idea of just adding a 314/2 to it, but I can't find anyone who knows what my joint is, nor what Predator would fit it. Sorry no pics, since my camera is already in Denver.
The joint on your cue should be 3/8 in. diameter and 14 threads to the inch.
It is very common because of Herman Rambow. Many shafts from Joss,
Schon, Richard Black, many Predators...etc...will inter-mix.
But I wouldn't advise using it for modern pool...I've had a few Hoppes and
one Rambow and they tend to be the old 3-cushion billiard thinking and you
are expected to grip them very short ( near the balance point)...the butt
is just too thick.
I strongly recommend seeing Measureman and Cuesblues at Hanks.