Yes, there are many posts in which you can be a class 1 officer through promotion.
- AAO:- It is a Group B gazetted post and very soon you will be promoted to Group A officer.
- Excise/custom Inspector: The promotions are slow here but after your 2nd promotion you can reach Group A gazetted post.
- Auditor/Accountant: If you clear the departmental exam SAS, you can reach Group A in some years.
- Assistant in CSS/MEA/Other Ministries: The promotions are slow here also but after a promotion or two, you can reach group A post.
Note: In some cases, Rank may not be promoted to Group A but according to MACP rule, salary can be promoted up to Group A level.