I don’t think the system would be allowed to allocate you seats unless they were available .... i.e I don’t think those seats would be allocated if it wasn’t the A320. Furthermore, I don’t believe denied boarded process at EZY works that way IF it is an A319.
If easyJet say there isn’t a problem then you should be reassured. Sometimes the problem with us that take an interest, is often we find problems that don’t exist as we look at the intricacies of things.
It does indeed look like that flight will be a 186 config aircraft with some planned Austrian registered aircraft for next month as things stand.....if that kind of thing interests you.