The strengths of individual Plastic Surgery programs will vary signifigantly (as do the strengths of any given ENT, General Surgery, Orthopedics, etc... divisions). Most commonly if there is a "weaker" area of many programs it is the aesthetic experience. In the past, most people drawn to academic plastic surgery were attracted to reconstructive surgery with the aesthetic business mostly done in the community, away from the teaching hospitals (which in many places people with insurance or money for cosmetic surgery will not go to for sociological reasons). As the reimbursements for traditional academic-style practices dried up, there has been retooling of many programs with more emphasis on aesthetic procedures for financial sustainability.
Back to your original question......
The aesthetic surgery training you get can vary a lot during residency for the integrated PRS & ENT. Extensive experience with aesthetics is pretty rare for most ENT programs at the senior levels. You should have however, picked up enough anatomy & technique to make the transition pretty easily into facial aesthetics with further training. Plastic Surgery (vs. facial plastic surgery) fellowships will likely give you better fundamental training & provide more flexibility for your practice in the long run. I met a number of people interviewing for Plastic Surgery who had previously done Facial Plastic Surgery fellowships and that felt limited in what they were now qualified to do. Out of the pool of patients considering cosmetic surgery, there are only so many facial aesthetic patients in that group- the extra training that gives you better standing to perform breast, abdomen, and body sculpturing will really pay off. PRS-boarded ENT's will give you the same advice.
I would surmise that most integrated programs get signifigantly more then 3 months worth of exposure during their 5,6, or 7 years (depending on the program model). Components of many of these procedures are also frequently major parts of craniofacial surgery & head/neck reconstruction which you perform pretty steadily. Its not rare for us to tack some essentially cosmetic embellishments on traumatic midface & periorbital operations. Hell...we do blephs and rhytidectomies on VA patients when we can get away with it. You point re. the aesthetic training available is something you should really look at when you are considering an integrated or tradition Plastic Surgery position.