Good opportunity
I have the same blocks on my 22. When looking to replace them I could not find ones that would fit the old holes, but I did not try D&R. In the end I just cleaned them up and reinstalled. Since your blocks are broken and not just old, this might be a good opportunity upgrade. Consider installing a track-mounted sheet block instead of a fixed-position block. If the track position is right, you might be able hide the holes from the old lead block. Yes, installing track and lead cars is more expensive but you will be able to better control your head sails and get better performance. I fiddled holding the sheets in different positions by hand last time I was out, and was amazed and how much it impacted and helped sail shape. Replacing the fixed leads with track is now on my winter project list.