Buffing the paint off, plus grinding a slight chamfer onto the leading edge of the seal will allow it to drive in without distorting the cover. Heating or freezing usually isn't necessary. I've been using those time-saver tricks over a lifetime of "flat rate" mechanic work to keep from starving to death. As long as the overall quality of the job doesn't suffer, time is money, and a few well-planned shortcuts will squeeze 10 hours' worth of labor pay into an 8-hour day most of the time.
Jerry
