b-60 transducer

[osprey]

Hi folks! I did a search on this ducer and didn't find an answer to my question. I have an 89 23cc. Up in the front locker, the drain is through an inner and outer layer with foam core. In the bilge toward the stern,I'm wondering if it is cored also. All the pictures of other installs show no coring. Just wonder if all years are like that. The installation is different if there is a core. Want to get as much info before I go and cut a hole in the bottom. Thanks