when you present yourself to the potential employers (with or without an MBA degree) the only thing which is considered by them is the quality of work experience.
some employers do stress on the type of job (permanent or contractual) however it is not the sole criteria for deciding the final job offer.
if your case, if the bank job gives you good knowledge and experience, then you must go for it.
also, have a look at this thread.
it might contain a similar query and a response.
I am an Indian IT professional with 4 yrs of work experience. I am planning to do my MBA in 2012.I am currently working in an Indian IT MNC as a senior developer and looking for a job change. I am offered being ITconsultant positions (for contract) in banks.Will my MBA prospects be affected if I take up contract positions instead of permanent jobs?
It would be great if you could guide me on this