Yes 1.77:1 is same as 16:9
As long as the resolution stays in standard definition (720x480), it's going to be 4:3. The show was copied from broadcast video tapes to DVDs, so it's SD quality and always.
If you watch the seperate season boxes or the Complete Collection which both are 4:3, you should be able to watch them both in 16:9, meaning the DVD player will automaticly stretch the image to fill the whole screen in HDTV. It's slightly distorted image, but only way to see it as rectangle without cropping the image. Playstation 3 was only player where I had to stretch the picture size manually to fill the whole screen.
Older DVD players may not stretch the 4:3 image to 16:9, so the picture stays square. I recommend also checking some setups if it's possible to do manually.