Is $1,300 to clean and remove mold, drywall, and some flooring a fair price?

I just bought my first home and paid $23,000 over asking price. The previous owners hid mold with their personal items during the home inspection, and I found it after moving in. The remediation company thinks the mold could be coming from a hole in the plywood, which would require removing all siding on that side of the house and redoing the plywood, costing thousands. However, my parents and I don't think the leak is from there. The business is coming back tomorrow to use an infrared light to find the source. My parents suggest just sealing the hole if it is the source, rather than re-siding the house. I feel like I can still see mold, even though they said they got it all. It just started pouring rain, which I hope will show if the leak is from the suspected area. I believe the mold was from the previous owners. I am hiring a different contractor that my family knows to finish the rest of the work, as I don't trust the current company. I will only let them do the infrared inspection.