Heater box removal question

IMG_2906.JPG Hi y'all,

The heater on my 1971 Scamp wasn't hooked up when I purchased it, so I decided to get it working to extend the cruising season. After researching the issue here on FABO, it loooked like a simple job. However, my box seems to be attached to the firewall in a manner that is not like the "typical" box. I don't seem to have the 4 bolts sorrounding the fan on the firewall like I'm seeing in the examples found. This leads to two questions, what kind of box do I have and how do I get it out??

I want to get my heater working, so once I get this box out, will I need to purchase a "normal" box and will I need some sort of adapter plate for the firewall?

Thanks,

Art