I would like to know whether it is possible to gain personal finance knowledge if a person works in a good finance firm where he comes across many financial models.
It depends what you mean by financial knowledge. Often you will work in a group focused on some aspect of the company's business. As an example, I work for a company and my group works on econometric models. Although I have a degree in finance, I don't encounter or talk about corporate or personal finance. I do talk about investing with a friend, but in general, our group is focused on one aspect of finance and economics for the company.
From another direction, often financial companies will offer financial literacy training through HR and benefits programs where you can improve your knowledge of finance outside of your groups focus.
In the end, you will learn the most by persuing new knowledge through reading on current financial literature. I hope this helps.
Edit: If you add some specifics to what you would like to learn about I may be able to point you in the right direction.