Man, those are nice. I was looking for something like that too: buckle back, no pocket design.
Are your 32's vanity sized? Could you give me a waist measurement on the 31's you have? Do you know what your true waist size is? How do they weigh? Are they still made in the US? I'm really considering them! haha.
Hey - turns out my 32 slim fits are actually tagged 33s, and are not vanity sized at all. They measure exactly 33 and 11.5 thigh. My new slim fit buckle backs are tagged 31 and actually measure 34, but the thighs are also 11.5. The legs seem almost identical to my sized 33 old ones. The buckle backs of course haven't been washed and my old slim fits are probably 6 years old, have been washed maybe 6 times or so, and dripped dry. My actual waist is 34 at my hips where I wear my jeans. I wear a 30 in low straights but had to go up a size on these to 31 because the thigh was too tight on the 30s. The buckle backs are US made, yup. Highly recommended. Their sizing is so screwy, but hope this helps.