"Elevated RDW and normal MCV is associated with the following conditions:
Early iron, vitamin B12, or folate deficiency
Dimorphic anemia (for example, iron and folate deficiency)
Sickle cell disease
Chronic liver disease
Excerpt from Medscape - Red Cell Distribution Width (RDW).
My lab doesn't measure RDW but I had a low normal MCV of 83 with severe vitamin B12 deficiency due to autoimmune pernicious anaemia. Doctors look for elevated MCV with the later stages of vitamin B12 deficiency but my high folate diet masked my pernicious anaemia. The video on youtube: "Diagnosing and Treating Vitamin B12 Deficiency" goes into more detail.
What are the ranges of your two tests. The ranges vary from lab to lab?
They could be boarder line and it wouldn't matter much. The RDW is generally that the red cells are showing variation in size and shape. This can come up in Iron deficiency and other things. What does the rest of your complete blood count look like? How are you feeling and do you have any symptoms? The first sign of B12 deficiency is tingling the fingers and hands. Also, fatigue. Did you have your iron, or ferritin drawn as well or anything else?