A stuck aperture on a Micro-Nikkor 55mm f/2.8 may be repairable, and disassembly guides do exist for this lens. However, based on the community advice, attempting the repair yourself is generally discouraged unless you are experienced with lens service. Opening the lens can introduce dust or even fungal contamination onto internal elements, which may create bigger problems than the original fault. If the lens is valuable to you, the safer option is to have it assessed by a professional repair technician rather than doing a full disassembly at home.