Swap from ac to none ac ?

[1972k5blazer]

Someone point me to a good answer I ve read a bunch of threads but get a little confused . My truck is a 71 all the ac stuff is there but I think I'd like to swap it out for a none ac inside heater box and use the ac delete firewall box I ve seen on here . I seen where there is a difference in the fire wall holes between none ac and ac but will a none ac box bolt right up to the firewall behind my glovebox and the ac delete plate bolt to the outside firewall and not have to cut or weld on the firewall to mate it up ? Thanks