modifying 67 cab for 70 ac - is it worth it?

[bucket]

i have my 67 big window cab stripped, ready for the blaster. i was planning on cutting holes for ac and modifying firewall for brake and fuse box for use on my 70. now i'm wondering if i shouldn't just switch the dash for a later one since the ignition bezels are different. aren't ash trays different too?

its in real good shape for midwest but it does need some floor and cab corner work. i'm pretty good at welding but i'm beginning to wonder if i shouldn't start with a later ac cab. thoughts?