If they're the PP96s - and I agree with Matt_wood55 that that's what they sound like - then their ("Delta") plates don't interchange with Keo plates.
However, the Delta plates are still available on Ebay, as are Delta compatible pedals, whether original Look or more modern copies. A lot of people have found that the modern Keo pedals don't offer the same bearing durability as the older versions, so there may be some virtue in keeping with the Deltas. For how long there will be good availability of pedals and / or plates is anyone's guess, though.