I would think that would be a good sign, yes. Once your appraisal is in, things should start to move a little faster.
A loan commitment letter tells you that the lender has committed to loaning you the money for your home purchase. This is a approval contingent upon appraisal, survey, conditions, etc. In other words, a conditional approval. If your conditions came attached to a letter from the lender and you are asked to sign it, it is a loan commitment letter.