I believe that they should be 36 inch scale diameter.
Do you have any way of measuring the diameter, such as a caliper or micrometer? A 36 inch scale diameter wheel should measure about 4.413 inch; a 33 inch scale wheel scale wheel should measure about 0.379 inch.
I just checked the stock wheels on some Athearn heavyweight cars, and they’re about .410", while those on an older car, with all-metal trucks, are a bit smaller at .400". While the trucks on the lightweight (corrugated) cars were different from those under the heavyweights, they all used the same-size wheels.