Your analysis is correct:
- All integers between -253 and 253 are exactly representable in double precision.
- The IEEE754 standard requires calculations to be performed exactly, and then rounded to the nearest representable number.
Hence a product of two values that equals an integer in that range will therefore be represented exactly.
Reference: What every computer scientist should know about floating-point arithmetic. The key section is the discussion of the IEEE standard as pertaining to operations. That contains the statement of the second bullet point above. You already knew the first bullet point and it's the second point that completes the argument.