Heater Core replacement 2000 Olds Intrigue

Trying to replace the heater core in my Intrigue. I've done heater cores before- perhaps a dozen. Mostly in the late 80's. Hate the job with a passion. Anyhow, does anyone know if the part labeled 2 on my uploaded diagram has to come out? Sure seems as if it does. Got all the bolts loose I could find so far. Still won't budge. Chilton manual no help- waste of money. (paperback version). Want to call it a plenum cause it looks like besides being the frame for the dash it also carries the air throught to vents.But they call the heater core casing the plenum. Any help would be greatly appreciated. Looks like I need to get it out to get the casing out.

Trying to replace the heater core in my Intrigue. I've done heater cores before- perhaps a dozen. Mostly in the late 80's. Hate the job with a passion. Anyhow, does anyone know if the part labeled 2 on my uploaded diagram has to come out? Sure seems as if it does. Got all the bolts loose I could find so far. Still won't budge. Chilton manual no help- waste of money. (paperback version). Want to call it a plenum cause it looks like besides being the frame for the dash it also carries the air throught to vents.But they call the heater core casing the plenum. Any help would be greatly appreciated. Looks like I need to get it out to get the casing out.

I'm pretty sure the dash does NOT need to come out on this one. The lower/under dash panels come off and the console comes out and you get to the core from underneath.

Broke down and paid for an AllData diy subscription. According to them it does have to come out. Thanks anyway.

I don't believe I had to remove that piece when I replaced the heater core. Let me know if you need any help.

The cross frame did not have to come out. Thanks.