Peterbilt Sleeper opening question

Hey guys, tried doing some research but I’m coming up blank. I want to take my 70in sleeper off my 379 and replace it with a 63in. A friend has a 63in in perfect condition and will let me hv it for free for some welding I did for him, only problem is his truck is a regular cab unibilt 379 while mine is a ultra cab 379. Is it worth the hassle to make the opening bigger to fit mine or am I better off to find another sleeper? Any input is appreciated

 

I was thinking that in the back of my head but sometimes you need to hear someone else say it lol. I think I’ll just sell that sleeper and find one for a ultracab like I have. Sorry it took such awhile to reply, had to put new rears in the ol girl and been chasing a flutter in the motor. Thanks man

 

Got backed into on the drivers side of the sleeper bout a month ago, and honestly I don’t stay out like I used to so a 63 will suit me just fine. Plus where I live I hv easier and cheaper access to a 63 vs a 70. I was gonna just replace the panel that got messed up but I think it will be easier and cheaper again to just switch to a 63 sleeper.