Yes, you can. I picked up the limited edition yesterday, installed the PS4 upgrade, and am using my previous PS4 saves. I had to delete the previous application data, not game save, for it to install properly. I was also able to get $34 for my PS4 copy today with the %100 trade bonus...
I was able to get IM 2 BR with Capn America Movie Money today at BB for $10 + tax after sale price and $5 coupon. No sign of the Cowboys & Aliens promotion yet.