It depends on the terms of your contract with that company.
If that company owns the work you did, then you have no rights to it.
If the company does not exist, it may be another story, but you should check to be sure, because if previous owners can claim rights, it could ruin any fruits the project bears for you.
Here's a hint: once you develop something once - you can do it 3x faster and 2x better the second time around - from scratch.
Remember that most of coding is 'figuring things out' - i.e. architecture, which apis to use, the requirements.
If you know exactly what you need to do and how to do it - you're 80% of the way there.
Just re-write it - it will be much better, and you save yourself any possible legal or moral issues.