I had the cylinder bored to the first oversize and have the oversize piston and a set of rings, no ring expanders came with the rings,  and there are no expanders under the rings on the original piston. Seems like there should be ring expanders.

You'll be good & i've seen them breakup on real old DT1's. Must admit i've used them on my old junk to try & force a bit of compression sealing out of a worn cylinder. Don't worry.

Thanks.