Dear Raji,
In so far as Central labor laws applicable to States and the State Governments also designated as appropriate Governments, there may be certain differences between the States in respect of criterion for applicability of some provisions of the Acts and certain procedural aspects in the Rules promulgated by the respective States.
For example, Chapter V-B of the ID Act, 1947, the minimum no of employees required for application of the Standing Orders Act,1946 and the no of contract labor required for taking Contractor's licence under the CLRA Act,1970. Similarly, the maximum no of punitive suspension prescribed under the Model Standing Ordres under the Central Industrial Employment Standing Orders Rules is just 4 days only whereas it is 30 days under the Tamilnadu State Rules.
In respect of State Labor Laws like Shops and Establishments Act, National and Festival Holidays Act, certainly there are differences which you can understand by taking a comparative study.
Similarly, certain States have their own special laws exclusively for certain employment conditions. In this connection, Maharashtra and Kerala have their own State laws for the prevention of unfair labor practices and recognition of Trade Unions whereas Tamilnadu has the Conferment of Permanent Status Act and the Payment of Subsistence Allowance Act. To my knowledge such exclusive laws are not available in other States.
Therefore, it is for you to get prepared well in advance by going through the State Labor Department Portal to know the provisions of the exclusive State Laws and the State Rules framed under various Central Laws.