In actual fact if anything they should be more important. It is true that there are differencce in the epithelium but that will almost certainly be outweighed by other considerations.
My reasoning is that postop trans women will tend to lack lubrication, this can cause local inflamation of the tissue. When tissue becomes inflamed the local vasculature will become leaky, you will get extraversion of neutrophils and lymphocytes from the blood vessels and release of prostaglandins and cytokines. Now while the presence of immune system cells in the tissue might provide some measure of protection against some pathogens, it does mean that a powerful barrier against infection has been breached. Inflamed, damaged tissue is easier for a pathogen to infiltrate, and ironically it would also increase your vulnerability to HIV because it logically it becomes more likely that a virus could find a suitable CD4 T-cell to target.
So taking normal precautions is still very advisable.
