I owned a Gold 71 Lesabre in the late 90s in the UK. I absolutely loved it. It had the rust problem under the rear window and the rear bumper as you mentioned was pushed up in the centre. Cool car especially around the narrow lanes of Devonshire! 😊
I remember seeing one about like this brand new when I was a teenager, I thought it was a really nice looking car. My parents then bought a new '72 Limited coupe the following year. In my opinion, the '72 refined what was started in '71 and had the most appealing styling for many years of what Buick did. Nice old survivor, equipped the way a lot of LeSabres were in the day. Basic with AC. The wheels were added by someone but still look great today.