you will be ok as long as you follow the clearances. clearances count to any protruding combustable material. I think the 02 wanted 12, the enviro wanted 10. Get the measurement 23 inches of hearth will be fine as long as the bay is no deeper then 5 inches on the 02, if it is to close, you will need to extend the hearth as well. Also check the manual for the 02 to make sure the floor protection does not require a certain r or k value.