While the vehicle could have different tires than the factory size by now, that size appears to be 235/70/16. 235/75/15 is the same width and as close as it gets to the same height so there would be no real visual difference as far as how much they fill the wheel well. The 15" would actually look a little larger because there's more rubber and less rim.
It would handle slighly sloppier due to the taller sidewall and speedo wouldn't be off enough to bother with getting a new speedo gear to change it. For example at 65MPH speedo reading you'd be going 64.83MPH, though your speedo might already be reading 1MPH above actual speed, or even more since the difference in diameter between new and worn out tires is more than between those two sizes.
I would prefer 16", but mostly to go taller and wider like a 255/70/16 without as much sidewall flex as going that direction on 15" rims. One thing about the 235/75/15 though, is that they're very inexpensive to run. I've had them on my '98 for 20 years and they've done fine.
