Only a guess here - but the Paris $25's look like the rack chips that are still in use as far as I know. So they should be cashable.

Paris is owned by Caesars Entertainment as is Horsheshoe next door. At an earlier time, the Ballys & Paris properties had a common ownership and may have even operated with a joint gaming license. The walkway that's open between the 2 properties, and the fact that at one time they had a $1 chip that said Paris on one side and Bally's on the other, leads me to think there was a common license at one time (and possibly still the case between Paris & Horseshoe-LV?

As for the Bally's chips. My guess is they would have had a redemption notice when Bally's exited the LV strip. It's owned by someone else too. You could try cashing them at the Horseshoe cage, but my bet is not-cashable. One final note, on one of the artist's drawings of the new A's ballpark where Tropicana was, there's also an "entertainment" complex with restaurants and a casino-hotel. That artist's rendering shows that the casino-hotel will be a Bally's. But it's years down the road and a different ownership than the place that made your Bally's chips.