As far back as I can remember, and as recently as last year's annual physical, I've always been weighed fully clothed on a scale in the hallway outside the exam rooms. A nurse would log the weight on my chart. Of course, that's only an approximation at best, due to the weight of clothing, shoes, etc.
There was a time from around age 10 to 18 when our family doctor had a scale with a height gauge in his exam room. I'd bet shown into the room by the nurse, directed to strip to my shorts and wait for the doc. He would do height, weight, temp, BP, etc. and then it was time to hop up on the table for the rest of the exam.
Now into retirement, weight control is an important health metric that everyone pays attention to. I still get weighed fully clothed on the scale in the hall. But for my own peace of mind, and as an incentive to watch my diet and exercise, I weigh myself in the nude every morning after my shower and a bowel movement, to get as close to a true weight as possible. My scale is in front of a full-length mirror, as an added incentive to eat properly and keep moving.
I keep a weight log using an app on my iPhone so I can see trends; and I share the "raw" data with my doctor at annual physical time. Same with the BP readings I take at the local Safeway from time to time. BP is always higher in the office; nervous effect, I expect.