Missing Thermostat lever for defiant.

I'm new here but have participated in forums before. Blown away that this forum exists. Lots of good info here. I believe I have a 1975 Defiant. Problem is there is no lever for the thermostat. Want to fix this. Post below talks about similar issue.
https://www.hearth.com/talk/threads/help-with-vc-defiant-1975-thermostat-cable-assembly.94915/
This link below shows a pic of maybe what I need?
http://www.blackswanhome.com/product/thermostat-older-vermont-castings
The attached picture is me holding my iphone behind the stove taking a picture of the thermostat housing with a view of the smole hole in the back. I'm thinking all I need is the lever but not sure how to attach it or (given the picture in the second link above) how that lever will stick out of that hole.

Will the housing need to come off to fix? If so what should I use to loosen the bottom screw on the outside of the assembly holding it on? I tried once and slipped and am scared to try again because I don't want to strip that screw/bolt. I'm not very handy but love burning wood. I've been propping the thermostat open with a metal rod to regulate the temperatuer which works very poorly

Any help is much appreciated.

I thought I knew what you were referring to when you said "older" Defiant, but now I'm not sure after seeing 1945 in your signature . Within the firebox itself, on the back, it has a 1975 stamp. It does have the solid cast iron doors. Picture attached for reference.

Also snapped a picture a little farther away from the thermostat housing. Thanks for your reply Browning.

I can only assume it does ( pretty sure). You can see from the second picture in my previous post there is a screw head sticking out a few inches under the hole in the thermostat housing. I tried once with about a 4 inch stubby flathead screwdriver and slipped. the metal seemed somewhat mushy...mabye i'm wrong. I was scared to try again. I'll figure this out I guess. Guess i'll spray something on the screw. Any tips for getting screws loose on a stove?

Guess I will try some PB Blaster.
https://www.hearth.com/talk/threads/how-to-loosen-stuck-screws.93177/

Ok. Dirty job but here it is. Props to those that said PB Blaster. Finally came loose but it was tightening both ways almost. Then when doing lefty loosely I stopped applying enough pressure to give me a hernia and it finally came out. Must have been forcing it back in. I don't know. What say u now that u can see the device?

Anyone else think this was rigged?

fbelec - assume u r saying that I shd order the part? If so I first want to make sure u don't mean this?
http://www.blackswanhome.com/product/443

Guess this is what happens when you try and find parts for antiques Anyways. Found this great website. Now I can say for sure that I have a Defiant III (Don't know about model 0019 or 0028). I can tell from parts 14 and 21. This place seems expensive but oh well. I'm gonna order part 27. This thermostat does have a different part number than some of the other older defiant thermostat listed in some of the other diagrams. http://www.cozycabinstoveandfirepla...s%5FWood%5FBurning%5FParts : Wood_Stove_Parts

I'm pretty sure of that as well now
http://www.fergusonfireplace.com/ferfirdefiantmenu.html
Still plugging away on my research and part procurement...

So frustrated guys. Hope u can offer advice. Just received part 5005467 which I know is the right part or at least think but see the first picture. The threaded end is smaller than the rigged screw that was in the hole. Any ideas? Also took two months to get part from VC but they were actually cheapest. Also according to manual I have it looked like the lever stuck up in the back. Not straight out. Maybe wrong part?

See the diagram as well. The lever sure does look like it sticks up in the back. What is the deal?!

bump. I still need help on this.

Wanted to post an update Please see the attached files that Vermont Castings support provided me. Unbelieveable support. I didn't include the email string for personal information. Basically I now need a 10-24 heli coil kit. I've ordered and will post back when installed.