What is the point of having the model? Doesn't gibbscam have a verify? (I know the answer is yes)
The verify should be all you need...(ESPECIALLY for a 2 axis lathe). It is really all you need for 3 and most 4 axis machines to make sure you have a program that is safe.
I'm not sure how a model would work dynamically in different software anyway. It would need to be Gibbs specific and have all of your tooling and offsets modeled in order to be really useful...(at least it would seem that way to me)
If you have all of your tooling drawn or represented accurately then you should be able to run verify and post and go.
The other answer is:
Buy a seat of this:
CGTech, the developer of VERICUT CNC simulation, optimization and verification software