I have modified openings in cabinet sizes and installed many appliances over the years including my last 2 double ovens. If it needs to be modified or if it will fit as is, I will let you know. I live in Hadley and I'm happy to come by. You can message me.

UPDATE:I I contacted Bailey Industries that did my original cabinets. They don't do this. " too much liability." Galaxy Cabinets don't answer the phone. I've called twice. My search will continue. Skilled carpenter perhaps? I have downloaded and printed installation specs for the old oven vs. the new oven. With my limited ability to understand this sort of thing, it looks like the opening is 1/2 inch too small.

Making a hole bigger - piece-a-cake.

Now trying to make a hole smaller? And look nice? hummpt

Take up Village Tinkerer on his offer.
It is a simple job for a good handyman if there is room with the face frame at the top.
Any cuts will be concealed by the oven flange.